- From: Jerome Euzenat <Jerome.Euzenat@inrialpes.fr>
- Date: Wed, 13 Nov 2002 18:37:35 +0100
- To: "Massimo Marchiori" <massimo@w3.org>, "pat hayes" <phayes@ai.uwf.edu>, "Jeff Heflin" <heflin@cse.lehigh.edu>
- Cc: <www-webont-wg@w3.org>
Hello,
In his message (RE: MT for imports (was: Re: Imports Proposal)) of 13/11/2002,
Massimo Marchiori wrote:
>Yes, that's precisely the major unanswered issue I was pointing out in
>http://lists.w3.org/Archives/Public/www-webont-wg/2002Nov/0117.html
>(and previous emails)
>"owl entailment would depend on the timed web structure"
>and raised as very first objection at the first telecon we had on this ;)
The timed web structure applies to ontologies exactly like it applies
to hyperlinks in html, xsl:include and xsl:imports in XSLT, etc.
So, my opinion that:
(1) we should not have to consider this, we should just consider the
state of the web at that moment;
(2) we should deal with it "gracefully", i.e. try to not be bothered
by failures. To that extend, I would suggest that if we fetch an
ontology it is added to the current one, if we cannot (404 or else)
it reduces to the empty set. This should not be that disturbing as
long as when there is more ontology, there is only less models and
thus more consequences (summary: the more 404, the less we can
deduce, but we still can).
The point is that, if we constraint too much the semantics on the
state of the web, we shall deduce nothing in a great number of cases.
If we do not state the semantics of import (or allow to ignore it),
then we might deduce too much (with regard to the designer's
expectations) in a number of cases.
Of course, imports are important and having a semantics for these is
part of the job. But, concerning the trouble of stacking owl:import
on RDF, I think this is a pity that RDF does not includes an
rdf:import.
If I remember well, there is a proposed xml:include somewhere as well
and I would have liked to see an owl:import based on an rdf:import
relying in its xml form on xml:include.
--
Jérôme Euzenat __
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Received on Wednesday, 13 November 2002 12:37:28 UTC