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Re: Axiomatic triples in OWL-R-Full?

From: Rinke Hoekstra <hoekstra@uva.nl>
Date: Wed, 9 Apr 2008 13:43:29 +0200
Cc: Michael Schneider <schneid@fzi.de>, W3C OWL Working Group <public-owl-wg@w3.org>
Message-Id: <C15FD50D-CC59-4691-B8AF-6AB9B610921B@uva.nl>
To: Ivan Herman <ivan@w3.org>

Hi Michael, Ivan,

On 9 apr 2008, at 12:38, Ivan Herman wrote:
> Maybe we should decide on the group this evening whether this should  
> be entered as an Issue

As a point of procedure: until now WG members just *raised* an issue  
whenever they deemed this necessary. We would then (shortly) discuss  
whether the WG would *open* the issue at the next telecon.

I see no reason to deviate from that procedure in this case.



>> The question whether to include axiomatic triples or not depends on  
>> whether we want the semantics of OWL R Full to be an upper  
>> semantics of RDFS or not.
>> Just one technical/theoretical remark for the moment: To receive  
>> strict RDFS compatibility, it is necessary to include all of the  
>> following axiomatic triples, for every natural language n:
> My understanding of Horst's paper is that _for a given graph_  
> calculating the RDFS closure (ie, by induction, the OWL-R-Full  
> closure, too) is doable because one can add only those rdf:_n  
> related axiomatic triples by limiting 'n' to the highest occurrence  
> of an rdf:_i usage in the original graph. I may have missed  
> something in fine print in the paper, but my understanding is that  
> this is perfectly doable, proper, and we would then get back to a  
> safe, finite world.
> But I yield to your knowledge of RDFS semantics...
> Ivan
>> From RDF semantics:
>>   rdf:_n rdf:type rdf:Property
>> From RDFS semantics:
>>   rdf:_n rdf:type rdfs:ContainerMembershipProperty
>>   rdf:_n rdfs:domain rdfs:Resource
>>   rdf:_n rdfs:range rdfs:Resource
>> Obviously, these are *infinitely* many axiomatic triples. In  
>> practice this would mean that complete OWL R Full conformance would  
>> probably not be possible to achieve. So it would be up to the  
>> implementors to decide about the intended conformance level of  
>> their product.
>> Cheers,
>> Michael
>> Ivan Herman wrote:
>>> (This may have to be raised as a more formal ISSUE. Also: it is  
>>> _not_ my intention to get this problem solved before the upcoming  
>>> publication round!)
>>> The current OWL-R-Full does not include 'axiomatic triples' to be  
>>> added to the resulting graph. What I mean is to add triples like
>>> (owl:FunctionalProperty,rdfs:subClassOf,rdf:Property)
>>> (rdfs:subPropertyOf,rdfs:domain,rdf:Property)
>>> etc. See for the RDF Semantics for a bunch of those in RDFS, and  
>>> Horst's paper on pD* for their OWL equivalents.
>>> I am not saying we must have those; this is clearly touching upon  
>>> the issue whether the core RDF/RDFS/OWL vocabulary is an object of  
>>> discourse or not in OWL-R-Full. We _could_ therefore, explicitly  
>>> say that those axiomatic triples are not defined in OWL-R-Full.  
>>> That would mean that some (valid) RDFS or OWL Full entailements  
>>> are not meaningful in OWL-R-Full, ie, OWL-R is also defined as a  
>>> syntactic restriction v.a.v. OWL 2 Full and not only OWL 2 DL.
>>> Again, I am not saying this is wrong. But the decision should be  
>>> made explicitly and documented in the profile document as well.  
>>> Alternatively, we could add those axiomatic triples for OWL-R-Full  
>>> (but then the relationship between OWL-R-Full and OWL-R-DL becomes  
>>> less clear...)
>>> Ivan
>>> -- 
>>> Ivan Herman, W3C Semantic Web Activity Lead
>>> Home: http://www.w3.org/People/Ivan/
>>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>>> FOAF: http://www.ivan-herman.net/foaf.rdf
>> --
>> Dipl.-Inform. Michael Schneider
>> FZI Forschungszentrum Informatik Karlsruhe
>> Abtl. Information Process Engineering (IPE)
>> Tel  : +49-721-9654-726
>> Fax  : +49-721-9654-727
>> Email: Michael.Schneider@fzi.de
>> Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
>> FZI Forschungszentrum Informatik an der Universität Karlsruhe
>> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
>> Tel.: +49-721-9654-0, Fax: +49-721-9654-959
>> Stiftung des bürgerlichen Rechts
>> Az: 14-0563.1 Regierungspräsidium Karlsruhe
>> Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi  
>> Studer
>> Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
> -- 
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf

Drs. Rinke Hoekstra

Email: hoekstra@uva.nl    Skype:  rinkehoekstra
Phone: +31-20-5253499     Fax:   +31-20-5253495
Web:   http://www.leibnizcenter.org/users/rinke

Leibniz Center for Law,          Faculty of Law
University of Amsterdam,            PO Box 1030
1000 BA  Amsterdam,             The Netherlands
Received on Wednesday, 9 April 2008 11:44:19 UTC

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