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Re: A possible way of going forward with OWL-R unification (ISSUE-131)

From: Ivan Herman <ivan@w3.org>
Date: Mon, 14 Jul 2008 16:04:14 +0200
Message-ID: <487B5CDE.6080309@w3.org>
To: Michael Schneider <schneid@fzi.de>
CC: Boris Motik <boris.motik@comlab.ox.ac.uk>, "OWL 1.1" <public-owl-wg@w3.org>
Hi Michael,

although you asked the question to Boris, let me test my understanding 
by trying to answer it:-) This may help all of us to clarify things... 
(I hope Boris does not mind)

Michael Schneider wrote:
> @Boris: In the description of the raised issue [1], you write:
>   """
>   - Section 4.3.2 would become Section 4.3
>     and we would call it "Reasoning in OWL-R and RDF Graphs using Rules".
>     The contents of the section would remain the same.
>   """
> This statement is about the actual rule tables. What I am wondering is how 
> this is supposed to work. The triple rules, clearly, aren't applicable 
> directly in a description logics version of OWL-R in general, and they look to 
> me very different from the actual specification of OWL R-DL in particular.
> I need to speculate, please comment: If I have an RDF graph, which is intended 
> to be an OWL-R ontology in RDF graph form, then:
>   (A) If I want to do RDF-based reasoning, I just use the triple rules as I 
> would do it in current OWL-R/Full.
>   (B) If I want to do DL-style reasoning, then
>       (1) I try to map the graph to functional style syntax by means of the 
> reverse RDF mapping.
>       (2) If the RDF graph could successfully be mapped,
>           then the resulting functional syntax is checked against the OWL-R 
> constraints
>           as provided by the Profiles document (still to be defined, of 
> course).
>       (3) If the functional syntax turns out to be a valid OWL-R ontology,
>           then the model-theoretic semantics as specified in the Semantics 
> document
>           are applied. These are then the OWL-R/DL semantics of this ontology.
> Is it this?

I think the point of OWL-R is that in, say, 95% of the cases (A) and (B) 
(well, by re-serializing the result of (B) into RDF, that is) the 
resulting set of RDF triples will be identical by some mathematical 
magic:-) There are some cases, however, where (B) will go wrong, 
(probably in step (1) already due to the the usage of, say, rdf:List), 
ie, (B) stops, whereas (A) would give a set of proper and predictable 
results. That is the issue we were haggling about with Boris... And the 
conclusion we seem to converge to is that there should be a name for, 
essentially the process (A) although we may not call it syntactic 
profile like the others.

I hope my understanding is correct!


> Cheers,
> Michael
> [1] <http://www.w3.org/2007/OWL/tracker/issues/131>


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

Received on Monday, 14 July 2008 14:04:49 UTC

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