Electronic Journal of Differential Equations, Vol. 1999(1999), No. 50, pp. 1-18. Title: A minmax problem for parabolic systems with competitive interactions Author: Sanjay Chawla (Univ. of Minnesota, Minneapolis, USA) Abstract: In this paper we model the evolution and interaction between two competing populations as a system of parabolic partial differential equations. The interaction between the two populations is quantified by the presence of non-local terms in the system of equations. We model the whole system as a two-person zero-sum game where the gains accrued by one population necessarily translate into the others loss. For a suitably chosen objective functional(pay-off) we establish and characterize the saddle point of the game. The controls(strategies) are kernels of the interaction terms. Submitted June 16, 1999. Published December 13, 1999. Math Subject Classifications: 49K35, 49K20, 49K22, 35K57, 45K05. Key Words: optimal control; game theory; saddle point.