THE MULTI-TYPE GALTON-WATSON PROCESS WITH IMMIGRATION

Summary We consider the limiting behaviour of a k-type (k < co) Galton-Watson process which is augmented at each generation by a stochastic immigration component. In Section 2, conditions for ergodicity are found for a subclass of such processes. In Section 3, expressions are derived for the first two moments of the nth generation (by way of a recurrence relation) and for the first two asymptotic moments, in a manner which to some extent generalises previous results.