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Re: Issue: Add hasValue to OWL Lite

From: Dan Connolly <connolly@w3.org>
Date: 29 Oct 2002 19:56:51 -0600
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: Deborah McGuinness <dlm@ksl.stanford.edu>, webont <www-webont-wg@w3.org>
Message-Id: <1035943012.23979.8553.camel@dirk>

On Tue, 2002-10-29 at 18:34, Ian Horrocks wrote:
> 
> The problem with adding hasValue to OWL Lite is that it wouldn't be
> Lite any more. The lack of hasValue in Lite is, from an implementation
> point of view, the main thing that differentiates it from fast -
> hasValue is very tough to deal with, and is responsible for pushing
> the worst case complexity of reasoning in fast OWL from ExpTime to
> NExpTime.

Could you unpack that a bit?

Could you give an example, maybe?

The rules for hasValue that occur to me are:

 holds(rdf:type, X, C) :-
	holds(P, X, Y),
	holds(owl:onProperty, C, P),
	holds(owl:hasValue, C, Y).


now that's only a partial specification of hasValue;
it allows you to come to hasValue conclusions, but
not to exploit hasValue claims in other ways.

I'm curious what people actually expect to do with hasValue,
and what makes hasValue difficult to deal with,
and whether they overlap.

If what people want to do is to say

	People with birthplace America are Americans
	Fred birthplace America
	=>
	Fred is an American

then that looks only horn-clause-hard.

But if they want to do something else, I can imagine
it would get harder.

> Ian
> 
> On October 26, Deborah McGuinness writes:
> > 
> > There have been requests to add hasValue to OWL Lite.  This is a
> > proposal to include hasValue in OWL Lite.

[...]
 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 29 October 2002 20:56:37 GMT

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