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Re: Proposal to resolve ISSUE-81

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Sun, 23 Mar 2008 14:16:42 -0400
Cc: "'Web Ontology Language \(\(OWL\)\) Working Group WG'" <public-owl-wg@w3.org>
Message-Id: <F9BE59B0-2BCE-4CDB-A92F-4878A232CDCA@gmail.com>
To: "Boris Motik" <boris.motik@comlab.ox.ac.uk>

On Mar 23, 2008, at 11:51 AM, Boris Motik wrote:

> Hello,
> What do you mean exactly with "transformed into equivalent class  
> assertion"?

I meant in the sense of a syntax macro, although I don't mind if it is  
pushed to the mapping level. One can envision a system where we have  
constructs that are equal participants at the functional style level,  
but who's definitions are given in terms of other functional level  
constructs. It was such a system in mind that I raised ISSUE-22.

> I believe that OWL 1.1 DL should explicitly support negative  
> property assertions at the functional-style and structural level:
> omitting a construct just because RDF cannot deal with it easily  
> sets a really bad precedent.

I'm not sure I understand the difference between the functional-style  
and structural level, and as you see I don't suggest not having the  
construct at a higher level. The characterization of the motivation is  
somewhat simplistic, however.  The RDF could handle it, but we are in  
a situation where a number of different constraints shape how well a  
particular solution works. In this case we benefit because there need  
no additional burden on the OWL Full semantics, and that there is also  
a benefit in forward compatibility - negative property assertions  
encoded in this way will be interpretable as OWL 1.0.

> I do believe, however, that such a translation would be acceptable  
> at the level of RDF mapping. We can think of whether we can use
> hints such as the one that you suggest below to enable round- 
> tripping. Even without round-tripping, I believe that such a solution
> would be acceptable in practice: saving a negative object property  
> assertion into RDF and reading it back would thus give you a
> class assertion that has an equivalent semantics.
> Regards,
> 	Boris
>> -----Original Message-----
>> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org 
>> ] On Behalf Of Alan Ruttenberg
>> Sent: 23 March 2008 14:48
>> To: Web Ontology Language ((OWL)) Working Group WG
>> Subject: Proposal to resolve ISSUE-81
>> To resolve this issue I propose that NegativeObjectPropertyAssertion
>> be transformed into the equivalent class assertion. In order to
>> support tools that wish to preserve the presentation of this axiom as
>> NegativeObjectPropertyAssertion we use the axiom annotation mechanism
>> with a new annotation property: syntaxHint.  syntaxHint would be
>> considered optional - not all tools need serialize using it, nor all
>> tool pay attention to it.
>> So
>> NegativeObjectPropertyAssertion(hasMother John Mary)
>> Is translated in to
>> ClassAssertion(
>>   Annotation(syntaxHint NegativeObjectPropertyAssertion)
>>   John ObjectAllValuesFrom(hasMother ObjectComplementOf(ObjectOneOf
>> (Mary))))
>> -Alan
>> meta: ISSUE-103
Received on Sunday, 23 March 2008 18:17:17 UTC

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