An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games

We consider the problem of computing mixed Nash equilibria of two-player zero-sum games with continuous sets of pure strategies and with first-order access to the payoff function. This problem arises for example in game-theory-inspired machine learning applications, such as distributionally-robust l...

Full description

Saved in:
Bibliographic Details
Main Authors: Wang, Guillaume, Chizat, Lénaïc
Format: Article
Language:English
Published: Université de Montpellier 2025-01-01
Series:Open Journal of Mathematical Optimization
Online Access:https://ojmo.centre-mersenne.org/articles/10.5802/ojmo.37/
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1825204986273857536
author Wang, Guillaume
Chizat, Lénaïc
author_facet Wang, Guillaume
Chizat, Lénaïc
author_sort Wang, Guillaume
collection DOAJ
description We consider the problem of computing mixed Nash equilibria of two-player zero-sum games with continuous sets of pure strategies and with first-order access to the payoff function. This problem arises for example in game-theory-inspired machine learning applications, such as distributionally-robust learning. In those applications, the strategy sets are high-dimensional and thus methods based on discretisation cannot tractably return high-accuracy solutions. In this paper, we introduce and analyze a particle-based method that enjoys guaranteed local convergence for this problem. This method consists in parametrizing the mixed strategies as atomic measures and applying proximal point updates to both the atoms’ weights and positions. It can be interpreted as an implicit time discretization of the “interacting” Wasserstein–Fisher–Rao gradient flow.We prove that, under non-degeneracy assumptions, this method converges at an exponential rate to the exact mixed Nash equilibrium from any initialization satisfying a natural notion of closeness to optimality. We illustrate our results with numerical experiments and discuss applications to max-margin and distributionally-robust classification using two-layer neural networks, where our method has a natural interpretation as a simultaneous training of the network’s weights and of the adversarial distribution.
format Article
id doaj-art-79554f456bf24ccca22cdeb6ec57a91e
institution Kabale University
issn 2777-5860
language English
publishDate 2025-01-01
publisher Université de Montpellier
record_format Article
series Open Journal of Mathematical Optimization
spelling doaj-art-79554f456bf24ccca22cdeb6ec57a91e2025-02-07T14:03:15ZengUniversité de MontpellierOpen Journal of Mathematical Optimization2777-58602025-01-01616610.5802/ojmo.3710.5802/ojmo.37An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous GamesWang, Guillaume0Chizat, Lénaïc1Institute of Mathematics, École polytechnique fédérale de Lausanne (EPFL), Station Z, CH-1015 LausanneInstitute of Mathematics, École polytechnique fédérale de Lausanne (EPFL), Station Z, CH-1015 LausanneWe consider the problem of computing mixed Nash equilibria of two-player zero-sum games with continuous sets of pure strategies and with first-order access to the payoff function. This problem arises for example in game-theory-inspired machine learning applications, such as distributionally-robust learning. In those applications, the strategy sets are high-dimensional and thus methods based on discretisation cannot tractably return high-accuracy solutions. In this paper, we introduce and analyze a particle-based method that enjoys guaranteed local convergence for this problem. This method consists in parametrizing the mixed strategies as atomic measures and applying proximal point updates to both the atoms’ weights and positions. It can be interpreted as an implicit time discretization of the “interacting” Wasserstein–Fisher–Rao gradient flow.We prove that, under non-degeneracy assumptions, this method converges at an exponential rate to the exact mixed Nash equilibrium from any initialization satisfying a natural notion of closeness to optimality. We illustrate our results with numerical experiments and discuss applications to max-margin and distributionally-robust classification using two-layer neural networks, where our method has a natural interpretation as a simultaneous training of the network’s weights and of the adversarial distribution.https://ojmo.centre-mersenne.org/articles/10.5802/ojmo.37/
spellingShingle Wang, Guillaume
Chizat, Lénaïc
An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
Open Journal of Mathematical Optimization
title An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
title_full An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
title_fullStr An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
title_full_unstemmed An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
title_short An Exponentially Converging Particle Method for the Mixed Nash Equilibrium of Continuous Games
title_sort exponentially converging particle method for the mixed nash equilibrium of continuous games
url https://ojmo.centre-mersenne.org/articles/10.5802/ojmo.37/
work_keys_str_mv AT wangguillaume anexponentiallyconvergingparticlemethodforthemixednashequilibriumofcontinuousgames
AT chizatlenaic anexponentiallyconvergingparticlemethodforthemixednashequilibriumofcontinuousgames
AT wangguillaume exponentiallyconvergingparticlemethodforthemixednashequilibriumofcontinuousgames
AT chizatlenaic exponentiallyconvergingparticlemethodforthemixednashequilibriumofcontinuousgames