W3C home > Mailing lists > Public > www-rdf-rules@w3.org > July 2005

Re: Web Rule Language - WRL vs SWRL

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Tue, 05 Jul 2005 11:17:17 -0400
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: www-rdf-rules@w3.org
Message-Id: <20050705151717.2B8D5CB5D3@kiferserv.kiferhome.com>

> On 1 Jul 2005, at 23:31, Michael Kifer wrote:
> [snip]
> I guess everyone is pretty bored with this by now (I know I am), and I 
> think we both made our positions clear.

Yes, guess we agree on this one :-)

Regarding SWRL/OWL-DL, of course I know that SWRL is an extension.

We are focusing on different things though. I am interested to see a use of
non-trivial SWRL rules (the delta above OWL-DL), which goes beyond simple Horn.
SWRL description goes beyond Horn (which is what makes this extension more
complex), and I was wondering if you could point me to a realistic use case
where those things are illustrated.

Anyway, I agree that we have exhausted this issue (and everybody else :-)
by now.


> One remaining point that may be worth clarifying, however...
> >> Regarding "the truly complex parts of SWRL, such as descriptions in 
> >> the
> >> head", I'm not sure what you mean by this. The SWRL rules given in the
> >> paper are used *in addition* to axioms such as the one above, and
> >> capture additional property relationships that cannot be expressed in
> >> OWL. In the general case, such rules lead to undecidability when
> >> combined even with OWL-Lite. Is that complex enough?
> >
> > Ian, you are not following. The discussion was about SWRL, not OWL.
> Now I understand your confusion. The important point you have missed is 
> that SWRL is an extension of OWL-DL: if you look at the specification, 
> you will see that SWRL is OWL-DL with the *addition* of a new kind of 
> axiom expressing Horn clause rules.
> > I was asking if you have examples of interesting uses of the more 
> > advanced
> > features of SWRL (not OWL) where complex rules are used. You pointed 
> > me to
> > this paper, but the rules there are very simple. So, this didn't 
> > satisfy my
> > curiosity. (Again, nothing against Christine's great project.)
> The interesting/advanced features involve the use of several kinds of 
> SWRL axiom, not just Horn clause axioms. That is what is going on here.
> I hope everything is now clear.
> Ian
> >
> >
> > 	--michael
> >
> >
Received on Tuesday, 5 July 2005 15:17:26 UTC

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