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Re: firts and rdf:rest as functional property

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Fri, 20 Mar 2009 14:14:14 +0000
Message-Id: <9AD32FB2-D839-4360-A58D-C44B1002B50F@cs.man.ac.uk>
Cc: Michael Schneider <schneid@fzi.de>, Semantic Web <semantic-web@w3.org>
To: Reto Bachmann-Gmür <reto.bachmann@trialox.org>
On 20 Mar 2009, at 14:02, Reto Bachmann-Gmür wrote:

> Hi Bijan
>> ...
>>> If rdf:rest
>>> and rdf:first are not functional a list could typically not be be
>>> splitted into different rdf molecules[1]. Splitting graphs into  
>>> small
>>> components is essential for applications like diff, sync[2] and
>>> versioning[3].
>>
>> If you are doing to decompose *semantically*, then functionality will
>> be too weak to do the job anyway.
> Not sure if I understand you, if a do decomposition of a graph into  
> RDF
> molecules[1] (as this is done in the Graph Versioning System GVS  
> [2]) if
> the base ontology contains the fact that rdf:rest and rdf:firts are
> owl:functionalProperty a list will typically (i.e. if some of the
> objects of the rdf:first statements are grounded or if the first
> rdf:List resource is grounded) be split into many small components  
> while
> otherwise it is (assuming the rdf:List resources are anonymous) all
> contained in one molecule. Isn't the decomposition into a semantical
> decomposition?

Sorry, don't have time to peek at that at the moment.

By semantic decomposition, I mean that there will be certain  
properties preserved in the decomposition. See the slides for:
	http://owl.cs.manchester.ac.uk/2008/iswc-modtut/

Functionality isn't necessarily the problem, but I presume you want  
first to be min1 as well (for a well formed list...having holes is as  
bad as having tentacles).

Functionality might have the surprising effect of entailing that two  
things are the same. Which might not be how you want to "repair" the  
tentacled list.

So, it's not clear to me that this is the right tool for the job.  
Perhaps I'm wrong about what job you're trying to do?

rdf:Lists were not introduced for modeling, but for encoding the  
syntax of OWL (taken from DAML+OIL). They have been pressed into  
service for modeling, but the built-in semantics (IMHO) as well as  
other aspects of them aren't really suited for modeling. But we model  
with what's at hand.

Cheers,
Bijan.
Received on Friday, 20 March 2009 14:10:35 GMT

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