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Re: owl:allValuesFrom inference

From: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>
Date: Thu, 25 Jun 2009 14:56:00 +0100
Message-Id: <129FD28D-B8AA-441E-AC02-CB722AF1656E@manchester.ac.uk>
Cc: Bernhard Schandl <bernhard.schandl@univie.ac.at>, Uli Sattler <sattler@cs.man.ac.uk>, Owl Dev <public-owl-dev@w3.org>
To: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>

On 25 Jun 2009, at 12:30, Sean Bechhofer wrote:

>
> 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.

<cough> Someone (thanks Peter :-) has pointed out to me that I'm  
wrong here. The triples above create an owl:Restriction, and then  
give it a name, which is not quite how I interpreted it. Note that  
this actually pushes you into OWL Full, as you're not allowed to name  
a restrictions in OWL DL.

> In M/cr syntax, it's saying:
>
> Class: ThingMadeByMan
>   SubClassOf:
>     madeBy some Man


The counterpart to the M/cr syntax I gave above would actually be  
something like:

ex:ThingMadeByMan
    owl:equivalentClass [
    a owl:Restriction ;
    owl:onProperty ex:madeBy ;
    owl:someValuesFrom ex:Man.].

e.g. stating that ThingMadeByMan is equivalent to the appropriate  
restriction.

As an aside, this also illustrates how easy it is (well, for me at  
least, anyway :-) to get confused by OWL represented as triples. I'd  
say it's much easier to see what's going on in an OWL (DL) model if  
it's presented using something like M/cr syntax.

Cheers,

	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 13:55:31 GMT

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