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[SKOS] ISSUE-36 ConceptSchemeContainment, skos:inScheme and rdfs:isDefinedBy

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Tue, 11 Dec 2007 19:44:19 +0100
Message-ID: <475EDA83.5060100@few.vu.nl>
To: SWD WG <public-swd-wg@w3.org>

Hi all

Concerning the action:
> *[NEW]* *ACTION:* Antoine to send a mail to the list so as to have a 
> discussion on ISSUE-36 and isDefinedBy for next week's telecon 
> [recorded in http://www.w3.org/2007/12/11-swd-minutes.html#action09]

I would propose that the WG discuss next week the mail I sent in October 
[0], which is attached below. I also propose that the WG adopts the 
resolution for ISSUE-36 that is contained there:

> 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."

where [3] was the proposal of Alistair which was agreed on during the 
F2F meeting.
The general idea is "we let the opportunity of using rdfs:isDefinedBy 
for some purposes open, but skos:inScheme is clearly what is needed for 
concept scheme membership and we keep it in the SKOS language".

Note the difference (wrt links between concept schemes and concepts) between the "to which it *belongs*" of the above proposal and the "in which it is *defined*" of [3]. And not that the sentence in which this "in which it is defined" appears is not removed from the text by adopting the above proposal. 

I would also propose that the action on Ralph to examine the semantics 
of rdfs:isDefinedBy

> *[PENDING]* *ACTION:* Ralph to reconstruct proposal for semantics of 
> isDefinedBy [recorded in 
> http://www.w3.org/2007/10/30-swd-minutes.html#action02]

to be re-formulated in a less exigent (but more constructive for the 
problem at hand?) way: "Ralph to check whether the common interpretation 
of rdfs:isDefinedBy fits the reasoning that was made in [0]."

Cheers,

Antoine

[0] http://lists.w3.org/Archives/Public/public-swd-wg/2007Oct/0141.html
[3] 
http://www.w3.org/2006/07/SWD/wiki/SkosDesign/ConceptSchemes/MinimalProposal?action=recall&rev=1




-------- Message original --------
Sujet: 	[SKOS] inScheme and rdfs:isDefinedBy (cf. ISSUE-36 
ConceptSchemeContainment)
Date de renvoi: 	Tue, 30 Oct 2007 16:59:42 +0000
De (renvoi): 	public-swd-wg@w3.org
Date: 	Tue, 30 Oct 2007 17:59:33 +0100
De: 	Antoine Isaac <aisaac@few.vu.nl>
Pour: 	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, 11 December 2007 18:45:49 GMT

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