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

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Thu, 6 Dec 2007 01:34:30 +0000
Message-Id: <7BEC42BA-239A-496D-B358-9C1C7F8B6997@gmail.com>
Cc: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>, 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>
Hi Jim,

Not all of OWL1.0 full is specified in the abstract syntax, just the  
part that is OWL-DL, no? For example, you can't use a bnode as a  
class name in the abstract syntax, but you can in OWL full, and you  
can't create a subclass of rdfs:List in the abstract syntax but you  
can in OWL Full.

Isn't this the same situation?

-Alan

On Dec 4, 2007, at 8:50 PM, Jim Hendler wrote:

> I have no trouble with that, except that implies that the  
> functional syntax cannot be the normative definition of the  
> language given our charter.  This is fine with me (i.e. as in OWL  
> the model theory is where the normative behaviors lie, and the  
> language is fully defined therein) but I go back to my first point,  
> we are not rejecting or postponing issue 83. We are accepting it  
> only in OWL 1.1 Full, and whichever document is the normative  
> definition of OWL 1.1 will need to include it as a possibility  
> (i.e. define whether this particular pattern of triples has any  
> additional semantics)
>  -JH
> p.s. I guess the functional syntax could be normative for OWL DL,  
> but it does mean we need to define where we put those  
> specifications of additional semantics qua Ian's response...
>
>
> On Dec 4, 2007, at 2:06 PM, Ian Horrocks wrote:
>
>> 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
>>>
>>>
>>>
>>>
>>
>
> "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 Thursday, 6 December 2007 01:35:02 GMT

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