Re: owl:allValuesFrom inference

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