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

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 19 Sep 2002 07:37:23 -0400 (EDT)
Message-Id: <20020919.073723.50043609.pfps@research.bell-labs.com>
To: heflin@cse.lehigh.edu
Cc: www-webont-wg@w3.org

From: Jeff Heflin <heflin@cse.lehigh.edu>
Subject: Re: LANG: syntactic version for imports (and other things)
Date: Wed, 18 Sep 2002 17:32:49 -0400

[...]

> However, I proposed that we use Pat's trick where there is an
> RDF domain of discourse with a subset that is the OWL domain of
> discourse. I would put owl:Ontology and owl:imports in the first set but
> not the second. If this is the case, what are the semantic problems with
> saying:
> 
> if ontology A imports ontology B then
> if B entails P then A entails P
> 
> It seems plain and simple to me.
> 
> Jeff

This is not plain, and certainly not simple.

Right now, semantic conditions say things like:

<x,p> in IEXT(IS(owl:onProperty)) and
<x,d> in IEXT(IS(owl:someValuesFrom))
only if 
ICEXT(x) = ICEXT(IS(owl:Thing)) ^ 
	   { x | exists y <x,y> in IEXT(p) ^ y in ICEXT(d)}

there is no mention of ontologies or entailment.

You want something like 

<o1,o2> in IEXT(IS(owl:imports))
only if 
ENTAIL(o1) >= ENTAIL(o2)

To make this work, you need a lot of machinery to support the ENTAIL
semantic relationship.  There are logics that have similar machinery, but
they are much more complex than first order logic.  

peter
Received on Thursday, 19 September 2002 07:37:33 GMT

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