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RE: ISSUE-83 (Vipul): Property Chain Axiom: P1 o P2 => P2 o P1

From: Kashyap, Vipul <VKASHYAP1@PARTNERS.ORG>
Date: Tue, 4 Dec 2007 09:41:36 -0500
Message-ID: <DBA3C02EAD0DC14BBB667C345EE2D1240180CC21@PHSXMB20.partners.org>
To: "Ian Horrocks" <ian.horrocks@comlab.ox.ac.uk>, "Uli Sattler" <sattler@cs.man.ac.uk>
Cc: <conrad.bock@nist.gov>, "Jeremy Carroll" <jjc@hpl.hp.com>, "OWL Working Group WG" <public-owl-wg@w3.org>


I am ok with postponing the issue till some folks decide to implement and
support it.

Need a small general clarification, I am assuming by implementation you mean
implementation of inferences?
There could conceivably be implementations focusing on data retrieval. 

Regards,

---Vipul

> -----Original Message-----
> From: Ian Horrocks [mailto:ian.horrocks@comlab.ox.ac.uk] 
> Sent: Tuesday, December 04, 2007 4:47 AM
> To: Uli Sattler
> Cc: conrad.bock@nist.gov; Kashyap, Vipul; 'Jeremy Carroll'; 
> 'OWL Working Group WG'
> Subject: Re: ISSUE-83 (Vipul): Property Chain Axiom: P1 o P2 
> => P2 o P1
> 
> To summarise: This is not allowed in the existing syntax, it would  
> lead to undecidability if it were allowed (even for very restricted  
> language subsets), it is not supported by implementations and seems  
> unlikely to be supported in the foreseeable future. I therefore  
> propose to postpone it on these grounds.
> 
> Ian
> 
> 
> On 3 Dec 2007, at 18:59, Uli Sattler wrote:
> 
> >
> > Hi Conrad -
> >
> > On 3 Dec 2007, at 15:38, Conrad Bock wrote:
> >
> >>
> >> Uli,
> >>
> >>>  makes reasoning undecidable (even R o S => T in general, ie,  
> >>> without
> >>>  the restrictions imposed by OWL 1.1 because it allows 
> you to reduce
> >>>  the intersection problem of contex-free languages to 
> satisfiability
> >>>  of concepts) ...
> >>
> >> Do you know of anyone working on restrictions that would make  
> >> chains in
> >> the "super" position (right hand side) decidable?
> >>
> >
> > I don't know of anybody currently working on it, but we know that  
> > it (having R o S => T o U)  makes reasoning undecidable in the  
> > logic that
> >
> > - has only IntersectionOf an SomeValuesFrom restrictions (see  
> > Baader, DL 2003, http://sunsite.informatik.rwth-aachen.de/ 
> > Publications/CEUR-WS/Vol-81/baader.pdf)
> >
> > - has only intersectionOf and AllValuesFrom Manfred 
> Schmidt-Schau .  
> > Subsumption in KL-ONE is undecidable. In Ron J.
> > Brachman, Hector J. Levesque, and Ray Reiter, editors, 
> Proc. of the  
> > 1st Int.
> > Conf. on the Principles of Knowledge Representation and Reasoning  
> > (KR'89),
> > pages 421-431. Morgan Kaufmann, Los Altos, 1989.
> >
> > Cheers, Uli
> >
> >> Conrad
> >>
> >>>  On 30 Nov 2007, at 14:53, Kashyap, Vipul wrote:
> >>>
> >>>>
> >>>>
> >>>> Would be interested in on the ramifications on the complexity of
> >>>> reasoning.
> >>>>
> >>>> ---Vipul
> >>>>
> >>>>> -----Original Message-----
> >>>>> From: public-owl-wg-request@w3.org
> >>>>> [mailto:public-owl-wg-request@w3.org] On Behalf Of 
> Jeremy Carroll
> >>>>> Sent: Friday, November 30, 2007 8:53 AM
> >>>>> To: OWL Working Group WG
> >>>>> Subject: Re: ISSUE-83 (Vipul): Property Chain Axiom: P1 o P2
> >>>>> => P2 o P1
> >>>>>
> >>>>>
> >>>>> OWL Working Group Issue Tracker wrote:
> >>>>>>
> >>>>>> ISSUE-83 (Vipul): Property Chain Axiom: P1 o P2 => P2 o P1
> >>>>>>
> >>>>>> http://www.w3.org/2007/OWL/tracker/issues/
> >>>>>>
> >>>>>> Raised by: Vipul Kashyap
> >>>>>> On product:
> >>>>>>
> >>>>>> I would like support for the property chain axiom.
> >>>>>> The use case is based on Alan Rector's example in the
> >>>  DL Handbook
> >>>>>>
> >>>>>> Skin of the finger is part of the skin of the hand.
> >>>>>> covers o part --> part o covers
> >>>>>>
> >>>>>> Thanks,
> >>>>>>
> >>>>>> ---Vipul
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> Interestingly, the constructs we already have, put this
> >>>  into the OWL
> >>>>> Full version of the language ...
> >>>>>
> >>>>> Jeremy
> >>>>>
> >>>>>
> >>>>
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> >>>>
> >>>
> >>>
> >>
> >>
> >
> >
> 
Received on Tuesday, 4 December 2007 14:41:54 GMT

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