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Hi Tom

My 0.02 on this

As a general remark, the more SKOS and DC are clearly interlinked, the
better :)

#1 : Complete agreement, being aware of consequences. If the domain of
skos:inScheme is open, its range is skos:ConceptScheme, so using this
property entails that any dcam:VocabularyEncodingScheme used as the object
of skos:inScheme is a skos:ConceptScheme. The following logical step is to
declare dcam:VocabularyEncodingScheme as a subclass of skos:ConceptScheme.
And the next one is asking what is specific to this subclass. If there is no
specificity, dcam:VocabularyEncodingScheme could as well (should?) be
replaced in the abstract model by skos:ConceptScheme. Do you want to go this
far in entailments?

#2 : In exemple in [1] seems to me that the two instances of rdf:value
should not use skos:prefLabel, the second one (EA32) is exactly a
skos:notation (of which domain is as open as the ones of skos:inScheme and
skos:prefLabel. See http://www.w3.org/TR/skos-reference/#notations

So the example revisited would look like the following ...

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:skos="http://www.w3.org/2004/02/skos/core#"
    xmlns:dcterms="http://purl.org/dc/terms/">

    <skos:ConceptScheme rdf:about="http://www.example.org/ns#ExampleSubjects
">
        <rdfs:label xml:lang="en">Example Subjects</rdfs:label>
    </skos:ConceptScheme>

    <rdf:Description rdf:about="http://example.org/123">
        <dcterms:subject>
            <rdf:Description rdf:about="http://www.example.org/subject32">
                <skos:inScheme rdf:resource="
http://www.example.org/ns#ExampleSubjects"/>
                <skos:prefLabel xml:lang="en">Biology</skos:prefLabel>
                <skos:notation rdf:datatype="
http://www.example.org/ns#SubjectEncoding">EA32</skos:notation>
            </rdf:Description>
        </dcterms:subject>
    </rdf:Description>

</rdf:RDF>

Granted, in this example, <http://www.example.org/subject32> is not declared
as a skos:Concept, but begins to look furiously like one :)
Nothing prevents to extend its description using other skos properties with
open domain, such as skos:altLabel, skos:definition ...

Bernard

2009/10/15 Thomas Baker <[log in to unmask]>

> Dear all,
>
> David Wood suggests two changes in how DCAM constructs are
> represented in RDF [1]:
>
> 1. Instead of using dcam:memberOf to relate a value to a
>   DCAM Vocabulary Encoding Scheme [1, section 4.5], David
>   suggests using skos:inScheme [2].
>
> 2. Instead of using rdf:value to relate a value to a
>   DCAM Value String [1, section 4.6], David suggests using
>   skos:prefLabel [3].
>
> Some first reactions:
>
> -- The domain of skos:inScheme was left unspecified in
>   order to provide the flexibility to extend a concept scheme
>   with classes of resource other than skos:Concept (i.e., the use
>   of skos:inScheme does not imply that the subject is a concept).
>   Also, skos:inScheme is better-known than dcam:memberOf.
>   So #1 seems like a sound idea.
>
> -- The domain of skos:prefLabel was also left unspecified [3],
>   so its use does not imply that the subject of a statement is
>   a SKOS concept.  On the other hand, I believe the
>   correct use of rdf:value has long been unclear.
>   So #2 seems like a good idea too, though as part of such a
>   change we would need to understand better where the problem
>   with rdf:value lies.
>
> Tom (at DC-2009, Seoul)
>
> [1] http://dublincore.org/documents/dc-rdf/#sect-4
> [2] http://www.w3.org/TR/skos-reference/#L2805
> [3] http://www.w3.org/TR/skos-reference/#L1541
>
> --
> Thomas Baker <[log in to unmask]>
>



-- 
Bernard Vatant
Senior Consultant
Vocabulary & Data Engineering
Tel:       +33 (0) 971 488 459
Mail:     [log in to unmask]
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