Mean-field analysis of Williams-Bjerknes-type growth

We investigate a class of stochastic growth models involving competition between two phases in which one of the phases has a competitive advantage. The equilibrium populations of the competing phases are calculated using a mean-field analysis. Regression probabilities for the extinction of the advantaged phase are calculated in a leading-order approximation. The results of the calculations are in good agreement with simulations carried out on a square lattice with periodic boundaries. The class of models are variants of the Williams-Bjerknes model for the growth of tumours in the basal layer of an epithelium. In the limit in which only one of the phases is unstable the class of models reduces to the well-known variants of the Eden model. (C) 1998 Elsevier Science B.V. All rights reserved.