On adding easy keys and top/bottom to the spec.

Hi,

I was not able to attend last week's meeting where top/bottom properties 
and easy keys were discussed. According to Alan and the minutes of the 
meeting, there seems to be some consensus on adding them to the spec. 

On easy keys, we find them useful and indeed easy to implement using DL 
Safe rules. So I have no objections in adding them to the spec. In terms 
of impact to existing profiles, I assume they can be easily added to 
OWL-R, but should be excluded from DL Lite.   How about EL++?

On top and bottom properties, I am not completely convinced by use cases 
given at [1]. Although use cases presented in Markus?s paper "All 
Elephants are bigger than all mice" are more compelling, they are use 
cases for concept product ? not universal property, which is just a 
special case of concept product.  I understand that they do not affect the 
worst case complexity of reasoning, but do we have any implementation 
experience about their practical impact?

Thanks!
Achille.

[1] http://www.w3.org/2007/OWL/wiki/Universal_Property
[2] http://www.korrekt.org/page/All_Elephants_are_Bigger_than_All_Mice