Re: SKOS Guide and owl:sameAs

Hi,

There is a confusion of different things here.

1- skos:Concept is a class.
2- instances of skos:Concept are called "concepts" in the SKOS documents.

3- mapping of skos:Concept to another class can be done with 
owl:equivalentClass
4- mapping of instances of skos:Concept to other skos:Concept 
instances (from other vocabularies) can be done with owl:sameAs
5- mapping of instances of skos:Concept to other instances (from other 
vocabularies) can also be done with the SKOS mapping properties, e.g. 
exactMatch [1]

Now the confusion is about which kind of mapping (3-5) is meant. The 
"Concept Identity and Mapping" section [2] states that mapping type 4 
should not be used, instead type 5 is better. This is because the 
former states that they are the same *in every respect*, while the 
latter only states that their extensions are the same (set of docs 
indexed with one concept is also properly indexed with the other). If 
you use the former you also merge their metadata, e.g. date of 
creation and scheme they belong to. They become indistinguishable. The 
latter keeps them distinguishable.

The text mentioned does not refer to type 3 at all. This mapping would 
be required if someone is not using the SKOS schema for a vocabulary, 
but  something similar. Then a mapping

	skos:Concept owl:equivalentClass my:Concept

can be used to make all instances of my:Concept also skos:Concepts, so 
they can be manipulated by software that understands SKOS.

Hope this helps,
Mark.

[1]http://www.w3.org/2004/02/skos/mapping/spec/#exactMatch
[2]http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#secidentity

Nabonita Guha wrote:
> */Bernard Vatant <bernard.vatant@mondeca.com>/* wrote:
> 
>  >A skos:Concept is not a class, and the domain of owl:equivalentClass is
>  >owl:Class
> 
> Whereas in SKOS Core guide 
> (http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#secconcept), 
> skos:Concept has been described as a class. If it's not a Class then 
> what it can be considered as?
> 
> Best,
> 
> Nabonita Guha
> 
> Senior Research Fellow
> Documentation Research & Training Centre
> Indian Statistical Institute
> Bangalore INDIA
> 
> 
> 
> 
> 
>     Hi Andrew
>      > The SKOS guide [1], in the "Concept Identity and Mapping"
>     section, states that owl:sameAs *should not* be used to indicate
>     that two concepts share the same meaning. It gives some rationale in
>     the section for this. Looking at the OWL guide [2], in the "4.1.
>     Equivalence between Classes and Properties" section, I'm wondering
>     whether one can use owl:equivalentClass to indicate that two
>     concepts share the same meaning. If there is a reason why
>     owl:equivalentClass can/cannot be used for this, should it also be
>     mentioned in "Concept Identity and Mapping" section?
>      >
>     Yes, there is a good reason.
>     A skos:Concept is not a class, and the domain of owl:equivalentClass is
>     owl:Class
> 
>     Cheers
> 
>     Bernard
> 
>      >
>      > Thanks, Andy.
>      >
>      > [1]
>      > [2]
>      >
>      >
>      >
> 
>     -- 
> 
>     *Bernard Vatant
>     *Knowledge Engineering
>     ----------------------------------------------------
>     *Mondeca**
>     *3, cité Nollez 75018 Paris France
>     Web: www.mondeca.com
>     ----------------------------------------------------
>     Tel: +33 (0) 871 488 459
>     Mail: bernard.vatant@mondeca.com
>     Blog: Leçons de Choses
> 
> 
> 
> ------------------------------------------------------------------------
> Want to start your own business? Learn how on Yahoo! Small Business. 
> <http://us.rd.yahoo.com/evt=41244/*http://smallbusiness.yahoo.com/r-index>

-- 
  Mark F.J. van Assem - Vrije Universiteit Amsterdam
        markREMOVE@cs.vu.nl - http://www.cs.vu.nl/~mark

Received on Wednesday, 1 November 2006 11:12:00 UTC