[protege-discussion] Refering to the same individual on a equivalency assumption/reasoning

[Thomas Russ]

Should be on the protege-owl mailing list.

On Apr 5, 2010, at 4:03 AM, João Cabrita wrote:

> Hi,
>
> I was having some trouble with getting a small equivalency reasoning  
> done.
>
> Here is an example of what I am trying to achieve in the equivalent  
> classes expression editor:
>
> Entity A and ObjectPropertyA some
>  (EntityB and (ObjectPropertyB some (EntityB and  
> inverseObjectPropertyA some EntityA)))
>
>
> Now let me try and explain to see if I am doing things correctly. I  
> want to have the individuals of EntityA that has 2 EntityB related  
> to it with the ObjectPropertyA and inverseObjectPropertyA while  
> those 2 EntityB are related with the ObjectPropertyB.
>
> For this to work correctly, I need that the individual refered in  
> the 2nd EntityA is the same than the first one, or else it could use  
> any individual that was an instance of EntityA instead of the same  
> one.
>
> Any ideas on how this could be done? Thank you for your help and time.

Well, in general you can't do this in OWL.  One of the expressivity  
restrictions is that you aren't able to make constraints between two  
property values on a single individual.  OWL 2.0 relaxes this a bit  
with the "self" restrictions, but I don't think you can actually  
express this particular restriction using OWL.  I think you can  
express this with SWRL, though.