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

From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
Date: Tue, 6 Nov 2007 14:58:10 -0000
Message-ID: <677CE4DD24B12C4B9FA138534E29FB1D0363C417@exchange11.fed.cclrc.ac.uk>
To: "SWD WG" <public-swd-wg@w3.org>

Hi all,

I agree with Antoine to re-open ISSUE-36. 

I also agree that there may be important differences between the semantics of rdfs:isDefinedBy and skos:inScheme, such that one cannot be a sub-property of the other. 

I suggest we divide the problem into two: 

First, we decide what we want to express. 

Then, we look at existing vocabulary, in particular rdfs:isDefinedBy and skos:inScheme, and see if we can use it. If not, we invent new vocabulary.

When discussing the first point, we must bear in mind that, as Guus has pointed out, OWL has no vocabulary for explicitly stating a relationship between a class, property or individual and the ontology in which it is defined. Yet, OWL applications have worked fine so far without need for any such vocabulary. Therefore, we must carefully consider which use cases establish a firm requirement for such vocabulary in SKOS, and why there are no analogous use cases for OWL. I.e. why is SKOS special?

To stimulate discussion of the first point only, I've written some ideas down at:

[1] <http://www.w3.org/2006/07/SWD/wiki/SkosDesign/ConceptSchemes/DiscussionPiece>

Note that this is not a proposal, just a discussion piece, illustrating one possible point of view and some of its consequences.

Cheers,

Alistair.

 

--
Alistair Miles
Research Associate
Science and Technology Facilities Council
Rutherford Appleton Laboratory
Harwell Science and Innovation Campus
Didcot
Oxfordshire OX11 0QX
United Kingdom
Web: http://purl.org/net/aliman
Email: a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440  

> -----Original Message-----
> From: public-swd-wg-request@w3.org 
> [mailto:public-swd-wg-request@w3.org] On Behalf Of Antoine Isaac
> Sent: 30 October 2007 17:00
> To: SWD WG
> Subject: [SKOS] inScheme and rdfs:isDefinedBy (cf. ISSUE-36 
> ConceptSchemeContainment)
> 
> 
> 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/M
> inimalProposal?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, 6 November 2007 14:58:33 UTC

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