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Re: question about DL/Lite semantics

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 05 Jun 2003 10:30:47 +0100
Message-ID: <3EDF0DC7.1060902@hplb.hpl.hp.com>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: jjc@hpl.hp.com, www-webont-wg@w3.org

reply pending ...
(I do not imagine being able to think about this until next week, however 
this looks like a substantive change, ...)

Peter F. Patel-Schneider wrote:

> This message from Jeremy points out an issue with the direct semantics.  In
> my haste to put in annotations, I make them relate individuals to
> individuals.  This has problems when the domain is very small.  For example
> AnnotationProperty(ex:a)
> ObjectProperty(ex:p Symmetric)
> SubClassOf(owl:Thing restriction(ex:p value(ex:x)))
> Individual(ex:x restriction(ex:p cardinality(1)))
> Class(ex:c1 annotation(ex:a ex:a))
> entails
> AnnotationProperty(ex:a annotation(ex:a ex:a))
> because there is only one individual (the interpretation of ex:x).
> However, this is not a valid entailment in the RDF semantics.
> I propose to fix this by modifying the direct semantics to admit ``junk''
> elements of the domain, i.e., elements of the domain that are not
> individuals.  This makes the direct semantics more ugly, but more like the
> RDF semantics.
> One side effect would be that Jeremy's entailment above would not hold,
> because <bar> would not have to be an individual.
> Comments?
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
Received on Thursday, 5 June 2003 05:31:14 UTC

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