Hi: I am not very familiar with DL. now I have to represent a class $A=\{x|(x,y) \in \neg R \wedge y \in C \}$ using DL can I use negated role provided by SROIQ. -- Nurmamat Helil Postdoctoral Candidate School of Computer Science and Engineering Chung-Ang University Seoul, 156-756, South Korea Email: nurmamat at gmail.com