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Re: Web Rule Language - WRL vs SWRL

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Tue, 5 Jul 2005 14:10:44 +0100
Message-Id: <916c72c4272daa7f2ba028ca6cf3f4a3@cs.man.ac.uk>
Cc: www-rdf-rules@w3.org
To: Michael Kifer <kifer@cs.sunysb.edu>

On 1 Jul 2005, at 23:31, Michael Kifer wrote:


I guess everyone is pretty bored with this by now (I know I am), and I 
think we both made our positions clear.

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.


> 	--michael
Received on Tuesday, 5 July 2005 13:10:50 UTC

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