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

If the group is happy, I am happy! :-)

Ivan

Phil Archer wrote:
> 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
> 
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
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