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Re: owl:allValuesFrom inference

From: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>
Date: Thu, 25 Jun 2009 12:30:39 +0100
Message-Id: <6678074F-CB20-460A-8116-B007ACA19AF9@manchester.ac.uk>
Cc: Uli Sattler <sattler@cs.man.ac.uk>, Owl Dev <public-owl-dev@w3.org>
To: Bernhard Schandl <bernhard.schandl@univie.ac.at>

On 25 Jun 2009, at 11:12, Bernhard Schandl wrote:

> Hi,
>
>> What you want to say is that *if something is madeby a Man (and  
>> possibly by some other things), then this something is a  
>> ThingMadeByMan.
>
> exactly.
>
>> So there direction of the implication needs to go the other way  
>> round an you need existential (someValues) restriction... in  
>> Manchester Syntax:
>>
>> Class: ThingMadeByMan
>>   EquivalentTo:
>>     madeBy some Man
>
> I'm not too familiar with Manchester Syntax, is this equivalent to  
> (n3):
>
> ex:ThingMadeByMan
>    a owl:Restriction ;
>    owl:onProperty ex:madeBy ;
>    owl:someValuesFrom ex:Man ;
> .

No. The N3 above is only asserting *subclass* here. In M/cr syntax,  
it's saying:

Class: ThingMadeByMan
   SubClassOf:
     madeBy some Man

So any instance of ThingMadeByMan must be madeBy some Man, but there  
could be things which are madeBy some Man which are *not* instances  
of ThingMadeByMan. So the inference that you want to draw doesn't  
follow (and the reasoner is behaving itself :-).

	Sean

--
Sean Bechhofer
School of Computer Science
University of Manchester
sean.bechhofer@manchester.ac.uk
http://www.cs.manchester.ac.uk/people/bechhofer
Received on Thursday, 25 June 2009 11:30:50 GMT

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