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Re: RDF and OWL compatibility

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Mon, 9 Jan 2006 14:07:49 +0100
Message-Id: <FABB460F-3374-453B-87B7-028711579A0E@inf.unibz.it>
Cc: Jos de Bruijn <jos.debruijn@deri.org>, Michael Kifer <kifer@cs.sunysb.edu>, W3C RIF WG <public-rif-wg@w3.org>
To: Dave Reynolds <der@hplb.hpl.hp.com>

On 5 Jan 2006, at 16:36, Michael Kifer wrote:
> Dave Reynolds <der@hplb.hpl.hp.com> wrote:
>> On the question of bNodes in the head, I hear the argument that it  
>> is not
>> sufficient to just treat these as new Skolem constants but my  
>> intuitive
>> understanding of the issue is too weak. It would be really helpful if
>> someone could construct a test case which demonstrates the  
>> difference in
>> results that arise between correct treatment of bNodes in the head  
>> versus
>> treatment as Skolem constants. In the concrete cases I've seen  
>> where bNodes
>> are used in the head of rules they seem to be intended as a form of
>> anonymous gensym - so the Skolem constant semantics may be the more
>> practically useful interpretation.
>
> Exactly. This was precisely one of the points in our J. Data Semantics
> paper,

And you can find in the use case <http://www.w3.org/2005/rules/wg/ 
wiki/Managing_incomplete_information> two examples (in section "9.4.  
(Rules involving generation of unknown)") which show how you can make  
things wrong with a naive use of skolem constants.

cheers
-e.
Received on Monday, 9 January 2006 13:08:07 GMT

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