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

>
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