Mean Field Games with Reflected Dynamics
Imane Jarni, Ayoub Laayoun, Badr Missaoui
TL;DR
This paper proves the existence of equilibria for Mean Field Games with reflected dynamics by formulating the representative-player problem in a relaxed control framework and recasting it as a controlled martingale problem. It establishes a fixed-point existence via Kakutani–Fan–Glicksberg for bounded coefficients and extends to unbounded coefficients through a truncation and limiting argument, ensuring the limit solves the RSDE with reflection and matches the mean-field law. The main contributions include extending Lacker's relaxed-control approach to reflected SDEs, formalizing control rules and their cost in a mean-field setting, and providing a rigorous existence result under Assumption (A) with both bounded and unbounded coefficient regimes. The results enable rigorous analysis of approximate Nash equilibria in large symmetric $N$-player games with boundary constraints and have potential applications in queueing networks, constrained stochastic control, and related areas where reflected dynamics arise.
Abstract
This paper establishes an equilibrium existence result for a class of Mean Field Games involving Reflected Stochastic Differential Equations. The proof relies on the framework of relaxed controls and martingale problems.
