[protege-discussion] Can't classify the OWL class properly, Why?

[Thomas Russ]

On Sep 2, 2009, at 7:01 AM, 刘康 wrote:

> if there are 3 class A, B, C is asserted, and A has the property pA.
> If defines the C with the assertion that C is the class A that the
> property pA only class B (NECESSARY & SUFFICIENT: class A, pA only B),
> I find the protege can't classify the individual properly, could you
> tell me why?

Open world.

Just because all of the KNOWN fillers of the property pA happen to  
belong to class B, it doesn't rule out the possibility that there is  
some UNMENTIONED filler of the property pA that doesn't belong to  
class B.

Open world means that classification using only, exact cardinality and  
maximum cardinality cannot be easily made.

There has to either be some direct assertion, or else you have to  
include some closure information such as asserting that the individual  
doesn't have any individual fillers except the ones that are known.   
This can be done by asserting that the instance belongs to the class  
(pA only {set of fillers of pA on the individual}).