Maximum principle for optimal control of interacting particle system: stochastic flow model
Andrey A. Dorogovtsev, Yuecai Han, Kateryna Hlyniana, Yuhang Li
TL;DR
The paper tackles stochastic control of interacting particle systems where the dynamics and costs depend on the random mass distribution $\mu_t=\mu_0\circ X(\cdot,t)^{-1}$. It develops a stochastic maximum principle by introducing a generalized backward SDE with interaction and proves its well-posedness using Lions differentiability for measure-valued arguments, enabling adjoint equations that account for the evolving mass. A Hamiltonian-based necessary condition is derived, leading to a forward–backward system with interaction that characterizes optimal controls, with explicit expressions in the linear-quadratic case. The results extend stochastic control beyond classical McKean–Vlasov dynamics by incorporating a random mass flow driven by a Brownian sheet, offering a principled route to optimal transport-like objectives for mass distributions and potential applications in controlled mass redistribution.
Abstract
In this paper, we consider the stochastic optimal control problem for the interacting particle system. We obtain the stochastic maximum principle of the optimal control system by introducing a generalized backward stochastic differential equation with interaction. The existence and uniqueness of the solution of this type of equation is proved. We derive the necessary condition that the optimal control should satisfy. As an application, the linear quadratic case is investigated to illustrate the main results.
