Re: OWL URI and namespace, an issue for LOV.

I think this is correct:
http://www.w3.org/TR/cooluris/#linking

But there's also this:
http://www.w3.org/2000/01/rdf-schema

On Jun 17, 2014 9:18 AM, "Bernard Vatant" <bernard.vatant@mondeca.com>
wrote:

> Hi all
>
> Sorry this looks like a permathread on namespaces and URIs, but hopefully
> someday someone will come out with a definitive and convincing explanation
> which will enlighten my old brain.
>
> We've been looking more closely in the OWL namespace publication, for
> inclusion into LOV cloud [1]. We'd been reluctant so far to include RDF,
> RDFS and OWL RDF schemas as ordinary LOV citizens, because of their
> particular status, but we are now experimenting it, in order to capture
> some information on how various vocabularies use RDFS or OWL, for example.
> In LOV we have some pragmatic rules, which are as difficult to figure as
> to enforce, to find out the vocabulary URI and the vocabulary namespace.
> They can be the same, or quite the same (differing by a final # or /, for
> example), or completely different. In the best of worlds, the vocabulary
> URI and the vocabulary namespace dereference ultimately to the same RDF
> file.
> Sometimes, the vocabulary URI dereferences, but not the namespace (in case
> of purl URIs, crazy things happen etc)
>
> We tend to trust what the vocabulary publisher declares, if it's
> consistent. If the vocabulary RDF file contains one predicate (?uri a
> owl:Ontology), and ?uri is dereferencing properly with or without conneg to
> the said file, we take ?uri to be the vocabulary URI.
> In the case of OWL either http://www.w3.org/2002/07/owl or
> http://www.w3.org/2002/07/owl# dereference to the same Turtle file, in
> which one can read :
>
> <http://www.w3.org/2002/07/owl> a owl:Ontology   (A1)
>
> So far so good. From the previous rule, we take
> http://www.w3.org/2002/07/owl to be the vocabulary URI, and
> http://www.w3.org/2002/07/owl# the associated namespace (defined in the
> prefix declarations).
>
> But, in the OWL elements definition, we read e.g.,
>
> owl:Class a rdfs:Class ;
>      rdfs:isDefinedBy <http://www.w3.org/2002/07/owl#>
>
> One would expect http://www.w3.org/2002/07/owl as the object of
> rdfs:isDefinedBy, to be consistent with (A1) above.
>
> It figures :
> - Are http://www.w3.org/2002/07/owl# and http://www.w3.org/2002/07/owl
> equivalent URIs? IOW should a RDF application (e.g., the LOV-Bot) consider
> them as the same resource?
> - If no, what is the rationale of using one here and the other there?
> - If yes ... same question :)
>
> In the current state of affairs, in LOV we add automatically in the
> back-end triple store a triple
> (?x  rdfs:isDefinedBy  ?uri) to every element ?x (class or property) found
> in a vocabulary, with ?uri being the vocabulary URI as above defined. Those
> triples add to the ones already declared in the vocabulary itself, if any
> (most of the time there are no such declarations).
>
> In the OWL case we will eventually have in the triple store the two
> following triples, one declared and the other one inferred :
>
> owl:Class rdfs:isDefinedBy <http://www.w3.org/2002/07/owl#>
> owl:Class rdfs:isDefinedBy <http://www.w3.org/2002/07/owl>
>
> This is noisy at best. The question is : should LOV change its rules
> regarding namespaces and URIs, or is the OWL schema broken?
>
> Thanks for your attention
>
> [1] http://lov.okfn.org/dataset/lov/details/vocabulary_owl.html
> --
>
> *Bernard Vatant*
> Vocabularies & Data Engineering
> Tel :  + 33 (0)9 71 48 84 59
>  Skype : bernard.vatant
> http://google.com/+BernardVatant
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