Complexity of ALCHOI (¬)

Dear friends:

I wonder if  the complexity of the DL ALCHOI (¬), i.e. ALCHOI with
negations on roles is already  known. I know it should be ExpTime-hard
(harder on ALCIO) and in NExpTime (since it is a subset of ALBO). I
wish to know the gap between these two has already been explored.
Thank you in advance for your concern.

Greets

Jie

-- 
Jie Bao
Department of Computer Science
Iowa State University
http://www.cs.iastate.edu/~baojie
baojie@cs.iastate.edu
515-294-7331(office), 515-509-3927(cell)