Optimal Control and Potential Games in the Mean Field
Felix Höfer, H. Mete Soner
TL;DR
The paper establishes a general bridge between mean-field control (MFC) and a potential mean-field game (MFG) of controls in a setting with non-Markovian dynamics, common noise, and jumps. By formulating an invariant value function and using a probabilistic coin-flip construction, it shows that minimizers of the MFC problem induce Nash equilibria of the associated MFG, including extensions to law-dependent dynamics. It also connects these mean-field constructs to Wasserstein gradient flows and provides a range of examples, such as price-interaction models, Kuramoto synchronization, and Cucker-Smale flocking, along with an explicit linear-quadratic case. An invariance principle ensures that the fundamental conclusions hold across different probabilistic representations, making the results robust for both stochastic and deterministic flow formulations. Collectively, the work broadens the applicability of potential mean-field games by accommodating jumps, common noise, and path-dependent interactions, with potential implications for economic, physical, and biological systems.
Abstract
We study a mean field optimal control problem with general non-Markovian dynamics, including both common noise and jumps. We show that its minimizers are Nash equilibria of an associated mean field game of controls. These types of games are necessarily potential, and the Nash equilibria derived as the minimizers of the control problem are closely connected to McKean-Vlasov equations of Langevin type. To illustrate the general theory, we present several examples, including a mean field game of controls with interactions through a price variable, and mean field Cucker-Smale Flocking and Kuramoto models. We also establish the invariance property of the value function, a key ingredient used in our proofs.
