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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 19:06:42 +0000
Message-Id: <479CA527-DFE5-4B42-A177-468C895F6985@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>
OWL Full permits *many* things that are not covered in the functional  
syntax. The functional syntax provides a "high-level abstract syntax  
for both OWL DL and OWL Lite" [1]. Such a specification is not  
necessary for OWL Full, as *any* RDF graph is an OWL Full ontology.  
Additional semantics may of course be given to certain (patterns of)  
triples as specified in the OWL Full semantics.

Ian

[1] http://www.w3.org/TR/owl-semantics/



On 4 Dec 2007, at 18:37, Jim Hendler wrote:

> 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 19:12:25 GMT

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