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RE: OIL Class Expressions in RDF

From: McBride, Brian <bwm@hplb.hpl.hp.com>
Date: Thu, 5 Oct 2000 05:59:06 +0100
Message-ID: <5E13A1874524D411A876006008CD059F239413@0-mail-1.hpl.hp.com>
To: "'Graham Klyne'" <GK@Dial.pipex.com>, "McBride, Brian" <bwm@hplb.hpl.hp.com>
Cc: Jeen Broekstra <jbroeks@cs.vu.nl>, www-rdf-interest@w3.org
> 
> >Further, the class of which herbivore is a subclass is of type
> >oil:not.  Herbivore is also a subclass of oil:not.
> >Intuitively, that feels very odd.
> 
> This may have more to do with the choice of names.   If the 
> names were 
> different:
> 
>    ([anon:cexpr], [rdf:type], [oil:NegationOfSomething])
>    ([anon:cexpr], [oil:theSomething], [#carnivore])
> 
> would it still feel so odd?

Woke up this morning and realised that I'd got this wrong.
herbivore is not a subclass of oil:not, its a subclass of
something of type oil:not.

> 
> I think the problem above is that you've assigned the same resource 
> identifier (anon:cexpr) to placeholders for two *different* class 
> expressions.  They may have the same value, but they're different 
> expressions. 

Thats what I'm having trouble getting.  They are two different 
class expressions, but they evaluate to the same class.  Is the
resource [anon:cexprA] a class or a class expression.

If it represents a class expression, then can it be subclassed?
If it represents a class then one gets operand problem I've
illustrated.  If its both, then does it conform to requirments
that a resource denotes a single entity?


>I think:
> 
> >([#herbivore],  [rdfs:subClassOf], [anon:cexprA])
> >([anon:cexprA], [rdf:type],        [oil:not])
> >([anon:cexprA], [oil:hasOperand],  [#carnivore])
> 
> >([#herbivore],  [rdfs:subClassOf], [anon:cexprB])
> >([anon:cexprB], [rdf:type],        [oil:and])
> >([anon:cexprB], [oil:hasOperand],  [cexpr1])
> >([anon:cexprB], [oil:hasOperand],  [cexpr2])
> 
> would be right, and keeps the classes and operands properly 
> attributable.

Yup - thats what one would do if they represent class expressions.

Brian
Received on Thursday, 5 October 2000 00:59:18 GMT

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