« Return to Thread: owl:allValuesFrom inference

Re: owl:allValuesFrom inference

by Uli Sattler :: Rate this Message:

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
>

« Return to Thread: owl:allValuesFrom inference