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Re: ACTION-203 done (resolution of ISSUE-118 - semantics of anonymous individuals)

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Fri, 29 Aug 2008 10:49:37 +0100
Message-Id: <F4153184-1E9F-4791-A11C-A7C967D6C350@cs.man.ac.uk>
Cc: W3C OWL Working Group <public-owl-wg@w3.org>, Boris Motik <boris.motik@comlab.ox.ac.uk>
To: Alan Ruttenberg <alanruttenberg@gmail.com>

First, these restrictions are perfectly global. That they *could be  
speced* with a grammar production is totally beside the point. I'm  
completely unmoved by worries that someone, somewhere might come  
along and complain that these restricitons aren't "really" global,  
especially on such weak tea as that possibility of inlineing that  
production.

Second, it's much preferable to have the general restrictions on  
anonymous individuals grouped in one place, e.g.,:

	No axiom in Ax of the following form contains anonymous individuals:
		SameIndividual, DifferentIndividuals,  
NegativeObjectPropertyAssertion, and NegativeDataPropertyAssertion.
	A forest F over the anonymous individuals in Ax exists such that,  
for each axiom in Ax of the form PropertyAssertion( P a1 a2 ) with P  
an object property and a1 and a2 anonymous individuals, either a1 is  
a child of a2 in F or a2 is a child of a1 in F.

This is much clearer than separating them. The second one is clearly  
global by any standard.

It's helpful for OWL Full as well, since you just drop those  
constraints the way you drop the regularity constraints.

Your profile/silent implementation worries just don't seem sensible.  
If there's a real concern then just munging the presentation of the  
syntax is like security by obscurity, a false assurance. People are,  
of necessity, going to implement various fragments and extensions and  
we shouldn't make it pointlessly harder for them or for people to  
figure out what they've done.

Finally, this would cause me to rethink my grudging support for this  
semantics.

Cheers,
Bijan.
Received on Friday, 29 August 2008 09:47:11 GMT

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