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Re: referencing a concept scheme as the code list of some referrer's property

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Wed, 22 Aug 2012 21:15:17 +0200
Message-ID: <50352FC5.3070802@few.vu.nl>
To: <public-lod@w3.org>, SKOS <public-esw-thes@w3.org>
Dear Thomas,

I'm ccing public-esw-thes@w3.org. Perhaps this was the one you were looking for!

(1) & (2)
You probably mean, if a ConceptScheme could be defined as a class, of which the concepts of a given concept scheme are instances?
That would be the way to proceed, if you want to use the concept scheme directly as the range of a property.
This is has never been suggested for inclusion in SKOS. In fact it is not forbidden, either. You can assert rdf:type statements between concepts and a concept scheme, if you want.
You can also define an adhoc sub-class of skos:Concept (say, ex:ConceptOfSchemeX), which includes all concepts that related to a specific concept scheme (ex:SchemeX) by skos:inScheme statements. This is quite easy using OWL. And then you can use this new class as the rdf:range.

The possibility of these two options makes it less obvious, why there should be a specific feature in SKOS to represent what you want.
But more fundamentally, it was perhaps never discussed, because it's neither a 100% SKOS problem, nor a simple one.
It's a bit like the link between a document and a subject concept: there could have been a skos:subject property, but it was argued that Dublin Core's dc:subject was good enough.
But it's maybe even worse than that :-) There are indeed discussions in the Dublin Core Architecture community about represent the link between a property and a concept scheme directly, similar to what you want. This is what is called vocabulary/value "encoding schemes" there [1].
But the existence of this feature at a quite deep, data-model level, rather confirms for me that it is something that clearly couldn't be tackled at the time SKOS was made a standard. One can view this problem as one of modeling RDFS/OWL properties, rather than representing concepts, no?

I'm not sure I get the question. If they exist, such mapping properties could be very difficult to semantically define. Would a concept scheme be broader, equivalent, narrower than another one?
Rather, I'd say that the property you're after indicates that some concepts from these two concept schemes are connected. For this I think one could use general linkage properties between datasets, such as voiD's linksets [2].

I hope that helps,


[1] http://dublincore.org/documents/profile-guidelines/ , search "Statement template: subject"
[2] http://vocab.deri.ie/void


This is about SKOS usage in LOD.

Yesterday I sent a post to public-swd-wg@w3.org, but obviously it has not been distributed, although it can be found in the archive.
public-swd-wg@w3.org isn't very active any more, so public-lod@w3.org might be a better place.

Best regards,

-------- Original-Nachricht --------
Betreff: 	referencing a concept scheme as the code list of some referrer's property
Datum: 	Sun, 19 Aug 2012 10:50:05 +0200
Von: 	Thomas Bandholtz <thomas.bandholtz@innoq.com>
An: 	public-swd-wg@w3.org


I came across several examples where concept schemes are referenced as
the code list of some property.
Usually this is done by two statements:

ex:property rdfs:range skos:Concept ;
         ex:codeList < [some concept scheme] > .

E.g. Data Cubes and geonames use this pattern, but one uses qb:codeList
to point to the scheme, the other gn:featureClass.

Regarding this, I have two questions:

(1) does someone remember a discussion why concept schemes should not be
expressed as subclasses of skos:Concept?
If subclassing  would have been used, any concept scheme could be
referenced in a single rdfs:type statement of the concept and a single
rdfs:range statement of the referrer.

(2) if there are sufficient reasons to insist in the current patterns,
shouldn't SKOS be extended by a standard property to be used by
referrers when they point to a concept scheme along with  a rdfs:range

And I add
(3) why do we not have mapping properties to link concept schemes from
different providers?
This cannot be inferred from a given concept mapping, as mapping of some
concepts does not imply mappings of their entire schemes.

Best regards,

Thomas Bandholtz
Principal Consultant

innoQ Deutschland GmbH
Krischerstr. 100,
D-40789 Monheim am Rhein, Germany
+49 178 4049387

http://innoq.com/de/themen/linked-data (German)
https://github.com/innoq/iqvoc/wiki/Linked-Data (English)
Received on Wednesday, 22 August 2012 19:15:48 UTC

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