Re: feedback on Easy keys and universal property

On 25 Apr 2008, at 17:38, Rinke Hoekstra wrote:
>
> Hi Zhe,
>
> I personally found Markus' paper "All Elephants are bigger than all  
> Mice" [1] a pretty convincing use case. Also, his work on SROIQ- 
> Rules and ELP is based on the availability of the top role.
[snip]

Yep, Alan Rector went on about this use case today at the Ontogenisis  
meeting. Crops up all the time in biology (and other areas).

I'll also add, again, that from a tool perspective, having symmetry  
between concepts and roles is useful. People will introduce a top  
property to have something to hang properties on. Also, having a top  
and a bottom property allows us to present certain key entailments  
(e.g., unsatisfiable properties).

Cheers,
Bijan.