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

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Tue, 4 Dec 2007 13:37:26 -0500
Message-Id: <148D24EA-3611-468B-9E60-7F4DB0AA2CC8@cs.rpi.edu>
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: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Not sure I understand this answer.  If the functional syntax won't  
cover the things that can be done in OWL 1.1 Full, then how could it  
be the normative definitions (note that I asked this same question  
with respect to inverseFunctional Datatypes and didn't get an answer  
there either).  If functional syntax is "functional syntax for OWL DL  
1.1." and there's some sort of addendum for those things in the RDF  
that aren't in the functional syntax, I can live with that - but the  
charter does mention maintaining OWL Full, so I find having a  
normative definition that doesn't include it confuses me.
  -JH
p.s. This is obviously more general a question than to this issue -  
but it does come up here.

On Dec 4, 2007, at 12:43 PM, Ian Horrocks wrote:

> 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
>>
>>
>>
>>
>

"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 18:39:39 GMT

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