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Re: Semantics question (was Re: XSLT question)

From: Phil Archer <parcher@icra.org>
Date: Wed, 23 Apr 2008 12:31:58 +0100
Message-ID: <480F1E2E.9050701@icra.org>
To: Public POWDER <public-powderwg@w3.org>

The projectionist shining his beam on my ignorance is right to have the 
power setting at maximum...

I followed the hyperlink to the OWL spec and, erm, sorry, I'm still a 
little unclear. Is this an 'individual'?

<rdf:Description rdf:about="#bbfc12">
   <ex:property>value</ex:property>
</rdf:Description>

If not, can you give me an example of something that is please?

Stasinos Konstantopoulos wrote:
> On Wed Apr 23 11:58:17 2008 Phil Archer said:
> 
>> OK, thanks very much Stasinos, that's hugely helpful. I've worked (and  
>> re-worked) through your comments on all this and would like to propose  
>> the following which, I hope, is in line with what you have said and, no  
>> less important, can be encoded in the XSLT that Kev is working on right 
>> now.
>>
>> I've prepared several examples of POWDER descriptor sets and their  
>> equivalent DR-S versions. Logically they begin with a simple one and end  
>> up hideously complex just to prove that the same rules can be applied  
>> and yield a consistent answer.
>>
>> So, the simple one first:
> 
> [snipped lots of easy calls]
> 
>> If the value of a property is a class then we have this situation:
>>
>> <descriptorset>
>>   <ex:property1>value</ex:property1>
>>   <ex:property2
>>       rdf:resource="http://example.org/semantic/powder.rdf#d1" />
>> </descriptorset>
> 
> But that was the whole point: the value of a property *cannot* be a
> class, it *has* to be in an instance.
> 
>> Which generates:
>>
>> <owl:Class rdf:nodeID="descriptorset_1">
>>   <owl:intersectionOf rdf:parseType="Collection">
>>     <owl:Restriction>
>>       <owl:onProperty rdf:resource="&ex;property1" />
>>       <owl:hasValue>value</owl:hasValue>
>>     </owl:Restriction>
>>     <owl:Restriction>
>>       <owl:onProperty rdf:resource="&ex;property2" />
>>       <owl:hasValue
>>          rdf:resource="http://example.org/semantic/powder.rdf#d1" />
>>     </owl:Restriction>
>>   </owl:IntersectionOf>
>> </owl:Class>
> 
> So, if "http://example.org/semantic/powder.rdf#d1" is of type
> "owl:Class", then this fragment is *not* OWL.
> 
> seeAlso http://www.w3.org/TR/owl-ref/#hasValue-def:
> 
>   The value constraint owl:hasValue is a built-in OWL property that links
>   a restriction class to a value V, which can be either an individual or a
>   data value.
> 
> [snipped lots of stuff invalidated by the previous statement]
> 
> s
> 
Received on Wednesday, 23 April 2008 11:32:37 GMT

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