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Re: owl:allValuesFrom inference

From: Irene Celino <irene.celino@gmail.com>
Date: Thu, 25 Jun 2009 15:25:24 +0200
Message-ID: <fa183ecc0906250625j326703c8v1306624f0244e6d6@mail.gmail.com>
To: Bernhard Schandl <bernhard.schandl@univie.ac.at>
Cc: Owl Dev <public-owl-dev@w3.org>, Uli Sattler <sattler@cs.man.ac.uk>
Bernhard,
I think that what you need in N3 syntax should look like the following:

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

Cheers,
Irene

Irene Celino

CEFRIEL - ICT Institute Politecnico di Milano

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2009/6/25 Uli Sattler <sattler@cs.man.ac.uk>

>
> 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 ;
>> .
>>
>> ... because I tried this one, but stil the implication
>>
>>
> hm, I'm not familiar with n3 syntax -- but i know that, in OWL, we have
> both "SubClassOf" and "EquivalentClass" statements -- and that it is
> important to distinguish the two...namely, if you say that X and Y are
> equivalent classes, then this has the same consequences as saying that X is
> a subclass of Y and Y is a subclass of X.
>
> Now, in your example, you want to infer *from* something being made by men
> that something is a ThingMadeByMan...for which you need the implication
> 'from right to left'...or in both directions.
>
>  This axiom together with your 2 assertions above about Bart and Something
>>> should then imply that Something is ThingMadeByMan
>>>
>>
>> is not derived by Pellet. :-(
>>
>> Also I wonder what a reasoner can actually infer from owl:someValuesFrom
>> -- as far as I can tell from the spec [1] it can actually only be used to
>> check the consistency of a model, but not to infer new facts, since the
>> reasoner cannot decide which of the (possibly many) values of the property
>> is an instance of the specified class.
>>
>
> I am not sure where this impression came from -- but its wrong, you can
> infer new facts: did you try your example? In your example, you have
> *stated* that Bart is a Man and that Something is madeby Bart; hence we (and
> the reasoner, too) can infer that Something is madeBy a Man and thus, if we
> also defined (!) things madeBy a Man to be   ThingMadeByMan, then we (and
> the reasoner) can infer that Something is a ThingMadeByMan.
>
> Cheers, Uli
>
>
>
>  Am I missing something here?
>>
>
>  Best, Bernhard
>>
>>
>
>
Received on Thursday, 25 June 2009 13:26:05 GMT

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