I am writing my thesis on the ACD model of Engle and Russel (1998). Because of the great similarities with GARCH, a common feature is non-degeneracy or non-degeneration. Apparently it is absolute basic knowledge, because I can figure out what non-degeneracy is. The ACD or GARCH process are basically stochastic processes. I would like to know what non-degeneration in context of a stochastic process is.



Non-degenerate stochastic process
A nondegenerate stochastic process has a nonzero variance, or equivalently, a nonzero diffusion coefficient.


