Variational mean field games for market competition

Abstract

In this paper, we explore Bertrand and Cournot Mean Field Games models for market competition with reflection boundary conditions. We prove existence, uniqueness and regularity of solutions to the system of equations, and show that this system can be written as an optimality condition of a convex minimization problem. We also provide a short proof of uniqueness to the system addressed in [Graber, P. and Ben- soussan, A., Existence and uniqueness of solutions for Bertrand and Cournot mean field games, Applied Mathematics & Optimization (2016)], where uniqueness was only proved for small parameters $\epsilon$. Finally, we prove existence and uniqueness of weak solutions to the corresponding first order system at the deterministic limit.