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

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Tue, 4 Dec 2007 17:43:25 +0000
Message-Id: <3E510B31-DF21-485B-B3CF-3712D11CCB48@comlab.ox.ac.uk>
Cc: Uli Sattler <sattler@cs.man.ac.uk>, <conrad.bock@nist.gov>, "'Kashyap, Vipul'" <VKASHYAP1@PARTNERS.ORG>, "'Jeremy Carroll'" <jjc@hpl.hp.com>, "'OWL Working Group WG'" <public-owl-wg@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>
It can already be expressed in the existing OWL Full in the sense  
that the relevant triples can be included in an OWL Full ontology. It  
cannot, however, be expressed in the functional syntax (which is also  
the case for inverseFunctional Datatypes in both 1.0 and 1.1).  
Extending the functional syntax would be undesirable for the reasons  
stated.

Ian


On 4 Dec 2007, at 17:22, Jim Hendler wrote:

>>
> My understanding from Jeremy's email in this thread is that in the  
> OWL Full version of 1.1 this can be expressed - if that is the  
> case, why is this postponed rather than accepted, but only for Full  
> (like we do for  inverseFunctional Datatypes)
>
>
>
> On Dec 4, 2007, at 4:47 AM, Ian Horrocks wrote:
>
>>
>> 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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>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
> "If we knew what we were doing, it wouldn't be called research,  
> would it?." - Albert Einstein
>
> Prof James Hendler				http://www.cs.rpi.edu/~hendler
> Tetherless World Constellation Chair
> Computer Science Dept
> Rensselaer Polytechnic Institute, Troy NY 12180
>
>
>
>
Received on Tuesday, 4 December 2007 17:44:01 GMT

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