Published online by Cambridge University Press: 01 July 2016
In this paper, a very general class of branching processes on the d-dimensional square lattice is studied. It is assumed that the division rates as well as the spatial distribution of offspring are configuration-dependent. The main interest of this paper is in the asymptotic geometrical behaviour of such processes. Utilizing techniques mainly due to Richardson [28], we derive conditions which are necessary and sufficient for such branching processes to have the following property: there exists a norm N(·) on Rd  such that, for all 0 < ∊ < 1, we have that almost surely for all sufficiently large t, all sites in the N-ball of radius (1 – ∊)t are contained in  (the set of sites occupied at time t) and
 (the set of sites occupied at time t) and  is contained in the set of all sites in the N-ball of radius (1 + ∊)t (given that the process starts with finitely many particles).
 is contained in the set of all sites in the N-ball of radius (1 + ∊)t (given that the process starts with finitely many particles).