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[SKOS] inScheme and rdfs:isDefinedBy (cf. ISSUE-36 ConceptSchemeContainment)

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Tue, 30 Oct 2007 17:59:33 +0100
Message-ID: <472762F5.8040709@few.vu.nl>
To: SWD WG <public-swd-wg@w3.org>

Hello,

Following the discussion today I have the following action:

> *[NEW]* *ACTION:* Antoine to summarise inScheme vs isDefinedBy and 
> decide whether or not to reopen the issue. [recorded in 
> http://www.w3.org/2007/10/30-swd-minutes.html#action03]

Minutes of the Oct 9 Face-to-face meeting [1] present the following 
(parts of a) resolution:

> > 1. for historical reasons, inscheme is kept as a subprop of isDefinedBy
> > we agree 3. that deprecating skos:inScheme (using approporiate owl 
> > vocab) is part of the accepted proposal

These extend Alistair's proposal for concept scheme semantics [3], which 
is also part of the resolution:

> The SKOS Primer also defines best practices for using rdfs:isDefinedBy 
> to explicitly state the relationship between a SKOS conceptual 
> resource and the concept scheme in which it is defined.

HOWEVER, it is questionable whether inScheme has an original meaning 
compatible with rdfs:isDefinedBy

As RDFS spec puts it [4]

> |rdfs:isDefinedBy| is an instance of |rdf:Property| 
> <http://www.w3.org/TR/rdf-schema/#ch_property> that is used to 
> indicate a resource defining the subject resource. This property may 
> be used to indicate an RDF vocabulary in which a resource is described.

As SKOS core guide puts it [5]:

> where you would like to assert that a concept is a part of a 
> particular concept scheme, use the |skos:inScheme 
> <http://www.w3.org/2004/02/skos/core/spec/#inScheme>| property,

The two properties therefore seem to have different motivations: 
rdfs:isDefinedBy is linked to the notion of definition, skos:inScheme to 
the one of containment. Elisa has cited the following in our last telecon:

>  If it's at all helpful, the "formal" definition of a "concept system" 
> from ISO 1087 is "a set of concepts structured according to the 
> relations among them". 

Furthermore, as SKOS spec [6] puts it:

> A concept may be a member of more than one concept scheme.

This could raise a problem: rdfs:isDefinedBy is not functional so can 
point at several resources. But it is expected that all these resources 
are expected to give a description of the defined resource. I don't 
think this would be the case for all the concept scheme a concept is 
member of. A concept will be for sure defined in some concept scheme, 
but I don't expect it to be defined in all the concept schemes it 
belongs to.

As a consequence, I PROPOSE TO RE-OPEN THIS ISSUE (which by the way is 
not closed, cf [7]) and make the following proposal for a resolution:

RESOLUTION: skos:inScheme is not deprecated, skos:inScheme is not a 
subproperty of rdfs:isDefinedBy. In accordance [3] can be kept, but 
adding inScheme in the proposed vocabulary as well as domain and range 
statements for this property. It should also include the following 
sentence: "The SKOS Primer also defines best practices for using 
skos:inScheme to explicitly state the relationship between a SKOS 
conceptual resource and the concept scheme(s) to which it belongs."


Antoine


[1] http://www.w3.org/2007/10/09-swd-minutes.html
[2] http://lists.w3.org/Archives/Public/public-swd-wg/2007Oct/0109.html
[3] 
http://www.w3.org/2006/07/SWD/wiki/SkosDesign/ConceptSchemes/MinimalProposal?action=recall&rev=1
[4] http://www.w3.org/TR/rdf-schema/#ch_isdefinedby
[5] http://www.w3.org/TR/swbp-skos-core-guide/#secscheme
[6] http://www.w3.org/TR/swbp-skos-core-spec/#inScheme
[7] http://www.w3.org/2006/07/SWD/track/products/3
Received on Tuesday, 30 October 2007 16:59:40 GMT

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