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Proposal to close ISSUE-69

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 10 Jan 2008 21:58:39 +0000
Message-Id: <4B5C0838-A65E-4987-8F61-75299B93DEBE@cs.man.ac.uk>
To: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>

ISSUE-69 claims that punning is incompatible with OWL Full because  
punning is "role bases" i.e., a URI "plays"  different roles  
(sometimes a class, sometimes an instances). In contrast, in OWL Full  
"this [ed. doesn't know what 'this' is] is identity".

While it's true that punning is weaker than Hilog semantics (in the  
sense of missing entailments) there is clear sense in which the  
semantics are compatible...punning is strictly weaker than the Hilog  
semantics. (Analogously, possibly finite owl:Thing is weaker than  
necessarily infinite owl:Thing.)

Jeremy claims that if we keep Hilog semantics for OWL Full and  
punning otherwise, we "weaken" the relationship between OWL Full and  
OWL DL. But this is arguably not true. For any legal OWL DL ontology,  
to the extent that its entailments coincide with the entailments  
under OWL Full semantics, the coincide in the presence of punning.  
That's because without punning, no ontology where a term is used in  
more than one role is an OWL DL ontology.

So everything that was true in OWL 1.0 is still true in OWL 1.1 with  
punning.

However, we can say some new stuff, that is, that there some  
ontologies (a subset of those with non-separated vocabularies) which  
now are legal OWL 1.1 ontologies (under punning semantics). Now we  
can only make somewhat weak claims about the coinciding of the  
entailments under the OWL 1.1 DL and Full semantics *of these new  
ontologies* (to wit, that the entialments under punning are a subset  
or equal to the entailments under Hilog). But note that the don't  
*always* diverge, or anything like that. So the situation is exactly  
the same as before, except the set of legal OWL 1.1 dl ontologies is  
a larger subset of all the RDF graphs.

We may want to discuss whether we thing hilog semantics is desirable  
over punning, but *this issue* claims that there is an  
incompatibility. I claim that there is no incompatibility. Thus we  
should close it. As there is no proposal in this issue, there's  
nothing to accept or reject.

Cheers,
Bijan.
Received on Thursday, 10 January 2008 21:56:56 GMT

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