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Re: Comment on POWDER WDR, 2008-06-30: exact translation of descriptorset into POWDER-S

From: Phil Archer <parcher@icra.org>
Date: Thu, 03 Jul 2008 14:57:53 +0100
Message-ID: <486CDAE1.3050508@icra.org>
To: Ivan Herman <ivan@w3.org>
CC: public-powderwg@w3.org

This is the necessary/necessary and sufficient issue I think?? We have 
discussed this previously and I believe we're happy the way it is but 
our OWL person (Stasinos) may be able to say more.

P

Ivan Herman wrote:
> Comment on http://www.w3.org/TR/2008/WD-powder-dr-20080630/
> 
> Looking at examples 2.2 and 2.3 and the way it is translated into 
> POWDER-S: the translation is an intersection of restrictions:
> 
> <owl:Class rdf:nodeID="descriptorset_1">
> 27      <owl:intersectionOf rdf:parseType="Collection">
> 28        <owl:Restriction>
> 29          <owl:onProperty 
> rdf:resource="http://example.org/vocab#color" />
> 30          <owl:hasValue>red</owl:hasValue>
> 31        </owl:Restriction>
> 32        <owl:Restriction>
> 33          <owl:onProperty 
> rdf:resource="http://example.org/vocab#shape" />
> 34          <owl:hasValue>square</owl:hasValue>
> 35        </owl:Restriction>
> 36      </owl:intersectionOf>
> 37      <dc:description>Everything on example.org is red and 
> square</dc:description>
> 38      <foaf:depiction rdf:resource="http://example.org/icon.png" />
> 39    </owl:Class>
> 
> 
> what this means, strictly speaking, is that if I take an instance of 
> that class, the 'color' or 'shape' properties will take that specified 
> values _if they are applied_. However, it does _not_ say that this 
> property _is_ applied on those instances. If the intention of the spec 
> is to say 'this and this property _is_ applied and it has this and this 
> value', then an extra cardinality restriction for each of those 
> properties might be necessary... It is up to the group to decide what 
> the intention is, though.
> 
> Cheers
> 
> Ivan
Received on Thursday, 3 July 2008 13:58:46 GMT

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