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Re: abstract class

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Thu, 23 Jan 2003 23:19:51 +0000
Message-Id: <5.1.0.14.0.20030123230724.0aa57860@localhost>
To: marc@jfcarrion.com, marc@jfcarrion.com, www-rdf-comments@w3.org

At 14:16 23/01/2003 -0800, Marc Carrion wrote:

[...]

> >
> > I understand that what you would like to be able to
> > do is to express the
> > fact that given:
> >
> >    sc1 rdfs:subClassOf c .
> >    sc2 rdfs:subClassOf c .
> >    c   rdf:type        rdfs:Abstract .
> >
> > there are no instances of c that are not instances
> > of either sc1 or sc2.
>   More or less, I would like to say that I don't have
>instances of c, that would be enough.

That would still be negation.  RDF cannot do that.

Think carefully about what you mean by "instance of".

In RDF, as has been pointed out on RDF interest, any instance of sc1 is an 
instance of c.  So when you say you want to say there are no instances of 
c, you would also be saying there are no instances of sc1 and no instances 
of sc2.  I doubt that's what you mean.

[...]

>   If anything identified with a RDF URI it's a
>Resource, why all the classes I define should extend
>from resource?

I don't know what you mean by "extend from".

Brian
Received on Thursday, 23 January 2003 18:18:51 GMT

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