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Re: LANG: syntactic version for imports (and other things)

From: Bernard Horan <Bernard.Horan@Sun.COM>
Date: Wed, 25 Sep 2002 11:35:38 +0100
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org
Message-id: <3D919179.19F5BBA1@sun.com>

Sorry to come to this party a little late... but I'm not convinced that
the decision you came to below works for me...

"Peter F. Patel-Schneider" wrote:
> 
> From: Jim Hendler <hendler@cs.umd.edu>
> Subject: Re: LANG: syntactic version for imports (and other things)
> Date: Mon, 16 Sep 2002 22:55:00 -0400
> 
> > I now fully understand the difference in understanding between me and
> > Peter - turns out there is something in the DAML+OIL model theory
> > that I never realized -- according to separate info that I received
> > from Peter and others, the following turns out to be legal DAML
> > (syntactically)
> >
> > 1)
> > URI1 has an ontology called AAA, including class XXX
> >
> > 2)
> > URI2 has an ontology called BBB,
> > and a class YYY that states it is a subclass of URI1:XXX.
> >
> > if I understand correctly, however, I am told that this means that
> > while YYY makes this claim, since it has no imports statement to AAA,
> > it as if this subclass statement didn't exist.
> 
> I can't imagine how you came up with this idea.  The second ontology
> certainly has all the effects of the subclass statement.
> 
> What is true, at least as far as I can see, is that information about
> referenced resources is not imported unless there is an imports statement.
> That is, if document 1 contains a DAML+OIL ontology including
>    YYY rdfs:subClassOf XXX .
> and document 2 contains a DAML+OIL ontology including
>    ZZZ rdfs:subClassOf YYY .
> but no imports statements, then the ontology in document 2 knows nothing
> about YYY being a subclass of XXX.

what's the consequence of this for a reasoner looking at document 2? 

Let's extend your example and say that document 3 contains a DAML+OIL
ontology including 
	AAA rdfs:subClassOf ZZZ
	AAA rdfsLsubClassOf YYY

without any imports statements. If I wish to point a reasoner at
document 3 to ensure that (say) it has no inconsistencies (in the same
way that I can point FaCT at an OilEd document), does this mean that I
have to indicate somewhere that the ontology in document 3 should
'import' the ontology in document 2? Should it also 'import' the
ontology in document 1? Or should it only 'import' the ontology in
document 1 if that ontology is not imported by the ontology in document
2? I.e. what's the transitive character of 'import' here? And how do I,
as a user, know which ontologies I should be importing??

cheers

Bernard
Received on Wednesday, 25 September 2002 06:34:01 GMT

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