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Re: Axiomatic triples in OWL-R-Full?

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 09 Apr 2008 07:28:54 -0400 (EDT)
Message-Id: <20080409.072854.118194953.pfps@research.bell-labs.com>
To: ivan@w3.org
Cc: schneid@fzi.de, public-owl-wg@w3.org

From: Ivan Herman <ivan@w3.org>
Subject: Re: Axiomatic triples in OWL-R-Full?
Date: Wed, 09 Apr 2008 12:38:24 +0200

> 
> 
> Michael Schneider wrote:
> > Hi, Ivan!
> > This is a good observation, and I think an issue should be raised for
> it.
> 
> Maybe we should decide on the group this evening whether this should be
> entered as an Issue
> 
> > The question whether to include axiomatic triples or not depends on
> whether we want the semantics of OWL R Full to be an upper semantics of
> RDFS or not.
> > Just one technical/theoretical remark for the moment: To receive
> strict RDFS compatibility, it is necessary to include all of the
> following axiomatic triples, for every natural language n:
> > 
> 
> My understanding of Horst's paper is that _for a given graph_
> calculating the RDFS closure (ie, by induction, the OWL-R-Full closure,
> too) is doable because one can add only those rdf:_n related axiomatic
> triples by limiting 'n' to the highest occurrence of an rdf:_i usage in
> the original graph. I may have missed something in fine print in the
> paper, but my understanding is that this is perfectly doable, proper,
> and we would then get back to a safe, finite world.

Nope, the RDFS closure of an RDF graph is infinite.  You can't get
around this.

What you can get around is that if you are checking an entailment in
RDFS, you can (as far as I know) only worry about some of the rdf:_i,
namely those that show up somewhere in either side of the entailment;
plus, maybe, some rdf:_i that doesn't show up. (I'm not sure on this
last.)  

Whether this works in OWL 1 Full is still open, as far as I know.  Even
if it works in OWL 1 Full, it would need to be separately shown for OWL
2 Full.

> But I yield to your knowledge of RDFS semantics...
> 
> Ivan

peter
Received on Wednesday, 9 April 2008 11:38:45 GMT

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