isAnon => cache

In this paper we generalize the martingale of Kella and Whitt to
the setting of Levy-type processes and show that under some quite
minimal conditions the local martingales are actually L^2 martingales
which upon dividing by the time index converge to zero a.s. and in
L^2. We apply these results to generalize known decomposition results
for Levy queues with secondary jump inputs and queues with server
vacations or service interruptions. Special cases are polling systems
with either compound Poisson or more general Levy inputs (joint work with Onno Boxma).