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Re: firts and rdf:rest as functional property

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 20 Mar 2009 10:53:49 -0500
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, Michael Schneider <schneid@fzi.de>, Semantic Web <semantic-web@w3.org>
Message-Id: <6BF0E6BC-CB07-4619-91EE-C07BC9EC36C5@ihmc.us>
To: Reto Bachmann-Gmür <reto.bachmann@trialox.org>

On Mar 20, 2009, at 10:49 AM, Reto Bachmann-Gmür wrote:

> Pat Hayes said the following on 03/20/2009 04:29 PM:
>> ...
>> Even if rdf: first (say) is owl:functionalProperty, this alone does
>> not constrain any RDF graph to contain any particular triples: the
>> molecular decomposition might still fail if information is missing
>> from the graph (as it always can be, regardless of the functionality
>> or otherwise of any relations.)
> I agree with your first point, that there is no way to constrain a  
> graph
> to contain a particular triple (even a cardinality constraint wouldn't
> do this), but I disagree with your notion of the possibility of  
> failure
> of decomposition into RDF molecules. The RDF molecules decomposition
> algorithm (and its exetnsion in GVS) always yields to a result, this
> result always satisfies the criterion of a lossless decomposition. The
> goal of small and mostly canonically serialized components can be
> compromised by the structure of the graph, but for real world graph  
> the
> algorithms are efficient to achieve it.

Sorry, "fail" was the wrong word to use. I realize it will always  
succeed in the sense you give here. My point was that this might not  
produce the complete list structure that you expect it to, when the  
RDF graph uses the LIst vocabulary, regardless of the functionality or  
otherwise of the relations.


> Cheers,
> reto

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Received on Friday, 20 March 2009 15:55:35 UTC

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