A non-asymptotic approach to stochastic differential games with many players under semi-monotonicity

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Cirant, Marco, Jackson, Joe, Redaelli, Davide Francesco
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908347037384704
author Cirant, Marco
Jackson, Joe
Redaelli, Davide Francesco
author_facet Cirant, Marco
Jackson, Joe
Redaelli, Davide Francesco
contents We consider stochastic differential games with a large number of players, with the aim of quantifying the gap between closed-loop, open-loop and distributed equilibria. We show that, under two different semi-monotonicity conditions, the equilibrium trajectories are close when the interactions between the players are weak. Our approach is non-asymptotic in nature, in the sense that it does not make use of any a priori identification of a limiting model, like in mean field game (MFG) theory. The main technical step is to derive bounds on solutions to systems of PDE/FBSDE characterizing the equilibria that are independent of the number of players. When specialized to the mean field setting, our estimates yield quantitative convergence results for both open-loop and closed-loop equilibria without any use of the master equation. In fact, our main bounds hold for games in which interactions are much sparser than those of MFGs, and so we can also obtain some "universality" results for MFGs, in which we show that games governed by dense enough networks converge to the usual MFG limit. Finally, we use our estimates to study a joint vanishing viscosity and large population limit in the setting of displacement monotone games without idiosyncratic noise.
format Preprint
id arxiv_https___arxiv_org_abs_2505_01526
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A non-asymptotic approach to stochastic differential games with many players under semi-monotonicity
Cirant, Marco
Jackson, Joe
Redaelli, Davide Francesco
Probability
Analysis of PDEs
91A15, 49N80, 60H30
We consider stochastic differential games with a large number of players, with the aim of quantifying the gap between closed-loop, open-loop and distributed equilibria. We show that, under two different semi-monotonicity conditions, the equilibrium trajectories are close when the interactions between the players are weak. Our approach is non-asymptotic in nature, in the sense that it does not make use of any a priori identification of a limiting model, like in mean field game (MFG) theory. The main technical step is to derive bounds on solutions to systems of PDE/FBSDE characterizing the equilibria that are independent of the number of players. When specialized to the mean field setting, our estimates yield quantitative convergence results for both open-loop and closed-loop equilibria without any use of the master equation. In fact, our main bounds hold for games in which interactions are much sparser than those of MFGs, and so we can also obtain some "universality" results for MFGs, in which we show that games governed by dense enough networks converge to the usual MFG limit. Finally, we use our estimates to study a joint vanishing viscosity and large population limit in the setting of displacement monotone games without idiosyncratic noise.
title A non-asymptotic approach to stochastic differential games with many players under semi-monotonicity
topic Probability
Analysis of PDEs
91A15, 49N80, 60H30
url https://arxiv.org/abs/2505.01526