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Re: Issue: Add hasValue to OWL Lite

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Wed, 11 Dec 2002 18:19:34 +0000
Message-ID: <3DF781B6.5040703@hpl.hp.com>
To: Jim Hendler <hendler@cs.umd.edu>
CC: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>, www-webont-wg@w3.org

> Sorry Ian, but all I've seen from you is pointers to work about 
> computational complexity -- and I just don't see that as a compelling 
> reason not to include an easy to implement, important feature that our 
> users are requesting.
> 



A test case:

s subclassof <rest onProperty p, hasValue x>
owl:Thing subclassof s
q type owl:ObjectProperty
p type owl:InverseFunctionalProperty

entails

q type owl:TransitiveProperty.

(Reason let a and b be two members of owl:Thing,
then a and b are both of type s, hence

a p x
b p x

hence

a sameInstanceAs b

i.e. the universe has cardinality 1).
Hence q is either the empty property or the complete property, and is 
transitive.

Parka doesn't do this (I assert without looking ...)


Using similar techniques the cardinality of the universe can be fixed as 
any finite number, and then complex reasoning about properties in finite 
sets is needed to work out which properties are transitive, symmetric etc.

Jeremy
Received on Wednesday, 11 December 2002 13:19:56 GMT

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