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Re: Proposal to resolve ISSUE-86

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Wed, 26 Mar 2008 15:50:11 +0000
Message-Id: <0DA6FE9A-5EE0-4AD2-B6F4-2214ABCD4FCD@cs.man.ac.uk>
Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, public-owl-wg@w3.org
To: Michael Smith <msmith@clarkparsia.com>

On 26 Mar 2008, at 13:45, Michael Smith wrote:

> On Sun, 2008-03-16 at 21:30 -0400, Alan Ruttenberg wrote:
>> RDF/XML serialization for anonymous inverse properties
>
>> I think it is beneficial to allow for anonymous inverses in
>> ObjectPropertyAssertion.
>
> Can you elaborate this?  If we don't have a real requirement for this,
> the simplest resolution* to ISSUE-86 is to require named object
> properties in object property assertions.

I thought of this solution and was unhappy.

> I.e., change
>
> objectPropertyAssertion := 'ObjectPropertyAssertion'  
> '(' { annotation } objectPropertyExpression sourceIndividualURI  
> targetIndividualURI ')'
>
> to
>
> objectPropertyAssertion := 'ObjectPropertyAssertion'  
> '(' { annotation } objectPropertyURI sourceIndividualURI  
> targetIndividualURI ')'

This seems unfortunate since I may then be required to introduce  
names for inverse properties *solely* due to abox statement. Indeed,  
if I *anticipate* people *ever* having to muck about with inverse  
property assertions, I'm forced to name *all* my inverse properties.  
It also means that I can't have collections of abox statements that  
transparently mimic the class expression structure, i.e., I might have:

	a:some.p(some.p- C)

(I.e., a has a p successor which has a p precessor which is a C)

but not:

	a p _:x. _:x p- C.

or
	a p b. b p- C.

Instead, I'd have to introduce an axiom naming p-. I think that's  
*much* less usable, not just because of name bloat, but because when  
you are describing relational structures it's often much easier to  
conceptualize it "navigationally". In general, inverse property  
expressions make the language more compositional, which, obviously, I  
like.

It is a place where the RDF is tricky, at best.

Cheers,
Bijan.
Received on Wednesday, 26 March 2008 15:48:40 GMT

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