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Re: OWL question

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 26 Sep 2002 23:49:43 -0400 (EDT)
Message-Id: <20020926.234943.45258216.pfps@research.bell-labs.com>
To: phayes@ai.uwf.edu
Cc: horrocks@cs.man.ac.uk, www-webont-wg@w3.org

From: pat hayes <phayes@ai.uwf.edu>
Subject: OWL question
Date: Thu, 26 Sep 2002 21:46:48 -0500

> Guys, should the following entailment be valid? (Intuitively, I mean; 
> Im looking for guidance here.)
> 
> AAA rdf:type owl:Restriction .
> AAA owl:sameClassAs owl:Nothing .
> 
> ?entails?
> 
> AAA owl:cardinality <xsd:integer: 0>
> 
> More generally, are there any valid OWL entailments with a conclusion 
> of the form
> 
> AAA <restriction-property> BBB .
> 
> but the antecedent does not mention a restriction property? I ask 
> because the only-if semantic conditions on restrictions seem to 
> suggest not, which seems odd.
> 
> Pat

Well one might think that this is something that one might want to infer.
However, there are several reasons why it is not a good idea.

1/ It verges on the extensionality principle, which, as we have discussed,
causes problems in OWL/RDF.

2/ OWL/RDF restrictions are compound constructs that are much more like
syntax than anything else.   It is rather strange to infer that some
resource *is* a piece of syntax.

So, in sum, it is the peculiarities of OWL/RDF that make the semantic
conditions on restrictions be only-if.

peter
Received on Thursday, 26 September 2002 23:49:58 GMT

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