W3C home > Mailing lists > Public > www-webont-wg@w3.org > June 2003

Re: question about DL/Lite semantics + agenda request

From: Jos De_Roo <jos.deroo@agfa.com>
Date: Fri, 20 Jun 2003 12:28:44 +0200
To: "Jeremy Carroll <jjc" <jjc@hpl.hp.com>
Cc: www-webont-wg@w3.org
Message-ID: <OF9527F59B.95290382-ONC1256D4B.002EDE69-C1256D4B.003992B2@agfa.be>


[...]

> but ...
>
> while
>
> > Class( <foo> annotation( <a> <bar> ) )
> > AnnotationProperty( <a> )
> > Class( <bar> )
> >
> does not now
> > entail
> >
> > AnnotationProperty( <a> )
> > Class( <foo> annotation( <a> individual() ) )
>
> we have that
>
> T(
> > Class( <foo> annotation( <a> <bar> ) )
> > AnnotationProperty( <a> )
> > Class( <bar> )
> )
> OWL Full entails
> T(
> > AnnotationProperty( <a> )
> > Class( <foo> annotation( <a> individual() ) )
> )
>
> because the individual() item is transformed into a bnode (with type
> owl:Thing?) and the type triple is trivially true, so that the OWL Full
> contentful part is:
>
> <foo> <a> <bar> .
> entails
> <foo> <a> _:b .
>
> which is true in RDF.
>
> This seems to be another instance of the "layering bug?" to which you
say:
>
> > if an entailment holds in OWL DL then it holds in OWL Full,
> > not vice versa.
>
> IMO it is worth highlighting this to the WG, and ensuring that the other
> documents capture this.
>
> for example, TEST needs to change to make it clear that an OWL Full
> consistency checker and an OWL DL consistency checker may get different
> results on a DL document.
>
> That's not good.

Right, and this one can't be resolved
by being agnostic about the extensions
of owl:Thing and owl:Class, at least
not that I can see.

--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Friday, 20 June 2003 06:29:00 GMT

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