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Re: Proposal to resolve ISSUE-86

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Fri, 28 Mar 2008 07:38:21 -0400
Message-Id: <B06B0FFB-4639-4572-A063-E85CBC57D136@gmail.com>
Cc: public-owl-wg <public-owl-wg@w3.org>
To: Michael Smith <msmith@clarkparsia.com>

I like your (2).
-Alan

On Mar 26, 2008, at 5:10 PM, Michael Smith wrote:

>
> The problem, as presented in ISSUE-86 is the representation of inverse
> object properties in *facts*, i.e., ObjectPropertyAssertions.  I  
> find it
> easy to get confused when we add to the discussion the use of object
> property expressions in restrictions, which does not have a problem in
> RDF.  I've limited my comments below to focus on object property
> assertions.
>
>
> Reusing the example fact from Boris's email [1],
>
> (1) ObjectPropertyAssertion( InverseObjectProperty( P ) i1 i2 )
>
>
> Proposal #1) Disallow this by modifying the definition of
> ObjectPropertyAssertion.  The following axiom (2) is logically
> equivalent.
>
> (2) ObjectPropertyAssertion( P i2 i1 )
>
>
> I believe this restriction matches OWL 1.0.  It was said on the  
> telecon
> that this does not meet the requirements of some stakeholders, the DIG
> community in particular was mentioned.  This brings us to
>
> Proposal #2) Allow these facts in the functional syntax but invert the
> assertion prior to the mapping to RDF.
>
> This allows (1) in the functional syntax but serializing it in RDF as
> (2).  Thus, it is not round-trippable through RDF.
>
> To which I'm sure some will reply that round-tripping through RDF is
> necessary.  So,
>
>
> Proposal #3) Allow these facts in the functional syntax but invert  
> them
> and add an annotation prior to the mapping to RDF.
>
> So (1) would be mapped to the following (3) before going to RDF.
>
> (3) ObjectPropertyAssertion (
> 	Annotation( owl11:invertedObjectPropertyAssertion  
> "true"^^xsd:boolean )
> 	P i2 i1
> 	)
>
> The annotation facilitates round tripping. I don't think that the
> details of the annotation are important, only its presence, and  
> consider
> the example above replaceable.  I find this solution attractive  
> because
> it limits the solution to the RDF to/from FS mapping, which reflects
> where the problem is.  The triple level details of this solution are
> dependent on the resolution of issues related to the mapping of
> annotations on axioms.
>
>
> I prefer any of the proposals outlined above to those proposed which
> require minting canonical inverse URIs for every property.
>
> Further, I believe that the approaches here will produce a more  
> elegant
> behavior in OWL 1.0 and RDFS tools that are not explicitly updated for
> OWL 1.1.
>
>
> Regards,
> -- 
> Mike Smith
>
> Clark & Parsia
>
> [1] http://www.w3.org/mid/001801c88f7b$10383e90$4012a8c0@wolf
>
>
Received on Friday, 28 March 2008 11:39:03 GMT

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