W3C home > Mailing lists > Public > public-owl-wg@w3.org > October 2007

Re: comments on RDF mapping

From: <ewallace@cme.nist.gov>
Date: Tue, 30 Oct 2007 17:01:20 -0500 (EST)
Message-Id: <200710302201.RAA29720@clue.mel.nist.gov>
To: jjc@hpl.hp.com, alanruttenberg@gmail.com
Cc: public-owl-wg@w3.org, rector@cs.man.ac.uk


Alan Ruttenberg wrote:
>My understanding is that there is a requirement to be able to create  
>properties attached to classes that have more inference support than  
>is currently possible using annotation properties. For example, it is  
>desirable that an "annotation property" for an editing time stamp  
>should have a range that is xsd:date, or, for SKOS, we would like  to  
>be create subproperties of rdfs:label.
>
>Alan Rector articulated these cases initially, IIRC. I suspect they  
>are recorded somewhere amongst  the OWLED stuff.
>
>I believe that you have correctly identified the missing entailments.  
>Those entailments, while desirable in general, are not necessary for  
>the above use case. As I understand it, the reason those entailments  
>are not supported is that there is not enough theoretical work to  
>ensure that they can be implemented in a sound, complete, and  
>decidable manner.
>
>Proponents of punning would label this:
>
>"OWL DL, now with more, but not all, of OWL Full goodness"
>
>I would suggest that instead of disallowing this use case, we instead  
>focus on adding whatever structural restrictions we can to reinforce  
>the desired future case - that the URI identifies a single thing. Off  
>the top of my head, for instance, we might add that no property in a  
>property chain be declared/used as a datatype property.
>
>-Alan

Alan's email message suggests to me that it would be very useful to have: 
motivations/requirements captured in some detail, the language feature(s) 
proposed to meet those requirements recorded, and the constraints/costs in 
language limitations that stem from those language features also recorded. 
That way we could better assess the costs of a new language feature against 
its benefits in the context of alternative solutions.  This demonstrates
considerable value in the traceability between these things for which Vipul 
has been arguing.

For example, the last language constraint described above would mean that we 
couldn't use property chains to describe properties that are derived datavalues.  
For me, that was the primary value in property chains.  I don't understand why
a simple non-logical annotation vocabulary as suggested recently by Vit Novacek
in [1] wouldn't achieve the original goals without this high cost.  On the other
hand, I don't think that the specific goals described above capture all of 
motivations for Punning.

I applaud the efforts of Bijan, Jeremy, and Vipul in documenting parts of this,
and I would like to help if we could identify a separable piece that I could
undertake.

[1] http://lists.w3.org/Archives/Public/public-owl-wg/2007Oct/0375.html
Received on Tuesday, 30 October 2007 22:02:07 GMT

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