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Re: Layering on what? was: Re: more on a same-syntax extension from RDF(S) to OWL

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 04 Mar 2002 18:59:22 -0500
To: jonathan@openhealth.org
Cc: jos.deroo.jd@belgium.agfa.com, www-webont-wg@w3.org
Message-Id: <20020304185922M.pfps@research.bell-labs.com>
From: "Jonathan Borden" <jonathan@openhealth.org>
Subject: Layering on what? was: Re: more on a same-syntax extension from RDF(S) to OWL
Date: Mon, 4 Mar 2002 18:35:32 -0500

> I am having a hard time following the layering threads. In the interest of
> simplifying this enough to penetrate my dense head:
> 
> 1) Are we talking about layering on RDF _as RDF is defined_ or
> 2) on N3, which seems to be used _as if_ it were RDF, but it is not at all
> clear to me how N3 is itself 'layered' on, or defined as an extension to,
> RDF
> 
> My preference at this point would be to 'layer' OWL on N3, whatever that
> means. My reasons are simply that N3 provides syntax for some seemingly
> important capabilities that are lacking in the current RDF syntax -- and I
> do not mean that RDF is serialized as XML, as one could create an XML
> version of N3, rather that the seemingly innocuous rdf:parseType="log:quote"
> hides some major advances in the RDF syntax, that (IMHO) would considerably
> change (and improve) RDF.
> 
> So for example, this discussion seems to be in N3, not RDF:
> 
> >
> > > > [...]
> > > >
> > > > > So, to be more precise it should have been
> > > > >
> > > > >
> > > > > log:entails
> > > > >   _:1 owl:oneOf ( _:2 ) .
> > > > >   _:2 a owl:Restriction .
> > > > >   _:2 owl:onProperty rdf:type .
> > > > >   _:2 hasClassQ _:1 .
> > > >         ^owl:
> > > > >   _:2 maxCardinalityQ "0" .
> > > >         ^owl:
> > > >
> ...
> >
> > good point, I've added
> >   { ?L owl:item ?x } log:implies { ?x a [ owl:oneOf ?L ] } .
> 
> How would one write the above in RDF?
> 
> This is important, because if we cannot even provide examples in RDF, how
> can we properly 'layer' OWL on RDF?
> 
> In any case, this seems like a fairly important discussion, but I am lost.
> 
> Jonathan
> 

Generally I try to use raw RDF, but occasionally, particularly if someone
else is so doing, I slip into an informal N-triples or N3 syntax.  My part
of the example above uses only parts of N3 that map well into RDF.

The problem with layering on N3 is that you can't really layer on something
that has no semantics. N-triples, on the other hand, has both a reasonable
syntax and a decent semantics (or soon will).  However, N-triples is really
nothing more than RDF.

peter
Received on Monday, 4 March 2002 18:59:44 GMT

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