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Re: Question about skos:concept

From: Thomas Bandholtz <thomas.bandholtz@innoq.com>
Date: Mon, 03 Aug 2009 22:05:41 +0200
Message-ID: <4A774315.2040008@innoq.com>
To: Jyotishman Pathak <jyotishman.mayo@gmail.com>
CC: Antoine Isaac <aisaac@few.vu.nl>, public-esw-thes@w3.org
Jyoti,

oops I was wrong - of course you are right.
Probably Antoine has given the better answer.

Anyway, why are you looking for a subClassOf relationship between
skos:Concept and rdfs:Resource?
For what do you need it?
I can hardly imagine a use case.

Thomas

Jyotishman Pathak schrieb:
> Thomas,
>
> My understanding is that the last bit of information in your email
> does not hold:
>
> rdfs:Resource
>     rdfs:Class
>        owl:Class
>           skos:Concept
>
> skos:Concept is rdf:type owl:Class (not subClassOf). So, I think the
> subClassOf hierarchy that you pointed out isn't holding...unless I am
> terribly missing something here.
>
> - Jyoti
>
> On Mon, Aug 3, 2009 at 12:44 PM, Thomas Bandholtz
> <thomas.bandholtz@innoq.com <mailto:thomas.bandholtz@innoq.com>> wrote:
>
>     Hi Antoine & Jyoti,
>
>     isn't it much more simple?
>
>     in OWL, "owl:Class is defined as a subclass of rdfs:Class" [1].
>
>     <rdfs:Class rdf:ID="Class">
>      <rdfs:label>Class</rdfs:label>
>      <rdfs:subClassOf rdf:resource="&rdfs;Class"/>
>     </rdfs:Class>
>
>     In RDFS you can read:
>
>     "2.1 rdfs:Resource All things described by RDF are called
>     resources, and
>     are instances of the class rdfs:Resource. This is the class of
>     everything. All other classes are subclasses of this class.
>     2.2 rdfs:Class This is the class of resources that are RDF
>     classes." [2]
>
>     <rdfs:Class rdf:about="http://www.w3.org/2000/01/rdf-schema#Class">
>      <rdfs:isDefinedBy
>     rdf:resource="http://www.w3.org/2000/01/rdf-schema#"/>
>      <rdfs:label>Class</rdfs:label>
>      <rdfs:comment>The class of classes.</rdfs:comment>
>      <rdfs:subClassOf
>     rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
>     </rdfs:Class>
>
>     That's why skos:Concept does not need a subClassOf rdfs:Resource,
>     it is
>     inherited.
>     Class hierarchy is:
>
>     rdfs:Resource
>        rdfs:Class
>           owl:Class
>              skos:Concept
>
>     Hope this helps,
>
>     Thomas
>
>     [1] http://www.w3.org/TR/owl-ref/#Class
>     [2] http://www.w3.org/TR/rdf-schema/#ch_resource
>
>
>     Antoine Isaac schrieb:
>     > Hi Jyoti,
>     >
>     > Indeed there is no explicit subClassOf relationship between
>     > skos:Concept and rdfs:Resource.
>     >
>     > But it is implicitly here: if I'm not mistaken, an RDFS/OWL
>     inference
>     > engine can get it from the RDFS and OWL semantics, especially using
>     > [1] which has the following axiom:
>     > If x is in IC then <x, I(rdfs:Resource)> is in
>     IEXT(I(rdfs:subClassOf))
>     > ( where IC = ICEXT(I(rdfs:Class)) )
>     >
>     > Cheers,
>     >
>     > Antoine
>     >
>     > [1] http://www.w3.org/TR/rdf-mt/#vocabulary_entail
>     >
>     >
>     >
>     >> Hello all,
>     >>
>     >> I am seeking a clarification about skos:concept.
>     >>
>     >> <rdf:Description rdf:about="#Concept">
>     >> <rdfs:label xml:lang="en">Concept</rdfs:label>
>     >> <rdfs:isDefinedBy
>     rdf:resource="http://www.w3.org/2004/02/skos/core"/>
>     >> <skos:definition xml:lang="en">An idea or notion; a unit of
>     >> thought.</skos:definition>
>     >> <!-- S1 -->
>     >> <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
>     >> </rdf:Description>
>     >>
>     >> 1.) At present, skos:concept is defined as an instance of owl:class
>     >> (and hence, an instance of rdfs:resource). However, I do not
>     see any
>     >> "explicit" subClassOf relationship between skos:concept and
>     >> rdfs:resource. Am I correct in assuming that such a
>     relationship does
>     >> not exist?
>     >>
>     >> 2.) If the answer to question# 1 is yes, could you please explain
>     >> (preferably with an example) why such an assertion was not included
>     >> in the specification?
>     >>
>     >> Thank you in advance for your replies!
>     >>
>     >> Cheers,
>     >> - Jyoti
>     >
>     >
>     >
>
>
>     --
>     Thomas Bandholtz, thomas.bandholtz@innoq.com
>     <mailto:thomas.bandholtz@innoq.com>, http://www.innoq.com
>     innoQ Deutschland GmbH, Halskestr. 17, D-40880 Ratingen, Germany
>     Phone: +49 228 9288490 Mobile: +49 178 4049387 Fax: +49 228 9288491
>
>


-- 
Thomas Bandholtz, thomas.bandholtz@innoq.com, http://www.innoq.com 
innoQ Deutschland GmbH, Halskestr. 17, D-40880 Ratingen, Germany
Phone: +49 228 9288490 Mobile: +49 178 4049387 Fax: +49 228 9288491
Received on Monday, 3 August 2009 20:06:17 UTC

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