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Re: ISSUE-83 (Vipul): Property Chain Axiom: P1 o P2 => P2 o P1 (really ISSUE-64)?

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Mon, 3 Dec 2007 09:04:15 +0000
Message-Id: <C5F09F13-8100-4FE8-90DB-B690B480AE6B@comlab.ox.ac.uk>
Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, Vipul Kashyap <VKASHYAP1@PARTNERS.ORG>, OWL Working Group WG <public-owl-wg@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>

To summarise: This is not allowed in the existing syntax, it would  
lead to undecidability if it were allowed, and it is not supported by  
implementations. I therefore propose to postpone it on these grounds.

Ian


On 3 Dec 2007, at 08:35, Bijan Parsia wrote:

> On Dec 2, 2007, at 10:14 PM, Alan Ruttenberg wrote:
>
>> Isn't this already permitted due to the resolution of issue 64?
>> http://www.w3.org/2007/OWL/tracker/issues/64
>
> No. That just changes the serialization of exisiting chain axioms.  
> It doesn't introduce new axioms though it does *allow* for new  
> classes of axioms e.g.,:
>
> """In OWL 1.1 Full one could use this everywhere, and not just in  
> the rdfs:subPropertyOf."""
>
> Note the "could".
>
>> (I added a note  to the issue clarifying what the resolution was  
>> and when it was resolved)
>>
>> -Alan
>>
>> On Dec 2, 2007, at 1:17 PM, Kashyap, Vipul wrote:
>>
>>> It is possible to extend the spec. to address this?
> [snip]
>
> It's possible to extend the spec. in any number of ways. The  
> question is whether anyone will implement it.
>
> Qua implementor, I would strongly prefer that such an extension go  
> under a rule extension such as SWRL. But I'll also say that I don't  
> know how to implement SWRL (or this extension) in a reasonable way.
>
> I would suggest lobbying your favorite implementors for such a  
> feature *before* trying to add it to the spec. Adding to the spec  
> doesn't, after all, magically make it available to you.
>
> Cheers,
> Bijan.
>
Received on Monday, 3 December 2007 09:04:32 GMT

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