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Re: ISSUE-44: BroaderNarrowerSemantics

From: Diego Berrueta <diego.berrueta@fundacionctic.org>
Date: Thu, 21 Jun 2007 13:30:49 +0200
To: SWD WG <public-swd-wg@w3.org>
Message-Id: <1182425449.4846.18.camel@duncan.fundacionctic.org>

El vie, 15-06-2007 a las 09:25 +0000, SWD Issue Tracker escribió: 
> What are the semantics of skos:broader and skos:narrower? There
> are several open questions:
>  * Are they transitive? Intransitive? Or can the application choose?
>  * Are they reflexive? Irreflexive? Or can the application choose?
>  * Should the transitive closure be irreflexive (i.e. a cycle is a
> contradiction)? Or can the application choose?

I agree with Daniel. In my opinion, letting applications to choose the
semantics is not a good idea; these properties should be transitive,
irreflexive and cycle-free. Moreover, if we finally agree on this, we
should change the SKOS documents to clarify this point. For instance,
the definition of skos:broader now reads "A concept that is more general
in meaning", but probably it should be changed to "A concept that is
*strictly* more general in meaning".

I think this has also an impact in the vocabulary mapping. For instance,
the cycle-free property makes impossible to import the OWL idiom of
making two classes equivalent by declaring them to be mutually
subClassOf each other. In other words, since the SKOS vocabulary mapping
is still a draft, people with an OWL background might be tempted to
express equivalence between SKOS concepts from two different schemas
using crossed "broader" (or "narrower") relationships.

Best regards,

Diego Berrueta
R&D Department  -  CTIC Foundation
E-mail: diego.berrueta@fundacionctic.org
Phone: +34 984 29 12 12
Parque Científico Tecnológico Gijón-Asturias-Spain
Received on Thursday, 21 June 2007 11:30:56 UTC

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