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Re: RE : [mawg] action-249: Ontology rev 5 available & call for competency questions wrt. to actor - role part of the ontology

From: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Date: Thu, 26 Aug 2010 10:31:28 +0200
Message-ID: <4C762660.1020005@liris.cnrs.fr>
To: "Evain, Jean-Pierre" <evain@ebu.ch>
CC: Tobias B├╝rger <tobias.buerger@salzburgresearch.at>, "public-media-annotation@w3.org" <public-media-annotation@w3.org>
On 26/08/2010 07:01, Evain, Jean-Pierre wrote:
> 1/ Actually, I had another look at the RDF specification for the use
> of UnionOf. I don't think it applies here.

which one? the 1999 specification was bugged in that respect
  http://www.w3.org/2000/03/rdf-tracking/#rdfs-domain-and-range

> Let' take another example...
> 
> We have the property 'location' (where a resource can be accessed
> from, typically a URI).  A locator can be assocaited to a media
> resource, a fragment or a named fragment.

the important word here is "or" !

If you state the following triples:

  ma:locator rdfs:domain ma:MediaResource . (1)
  ma:locator rdfs:domain ma:Fragment . (2)

then each of those triples can be considered independantly of the other.
Now consider

  :res1 ma:locator :loc1 . (3)

>From (1) and (3) I can infer that :res1 is a ma:MediaResource.
>From (1) and (2) I can infer that :rest1 is also a ma:Fragment.
In other words, you have stated with (1-2) that a locator can be
associated to (something that is) a media resource *and* a fragment.

The only way to express the "or" in your sentence above is to use a
owl:unionOf .

> Therefore it make sense to
> say that the property location is multirange. It will be used to
> generate valid clearly separated triples.  I can't see the use of
> UnionOf here. Or?

I agree that aggregating all this in a unionOf construct is a bit
awkward, but this is required: separate triples have a *conjunctive*
semantics.

  pa
Received on Thursday, 26 August 2010 08:32:05 GMT

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