Synchronization in Learning in Periodic Zero-Sum Games Triggers Divergence from Nash Equilibrium

Fuente: arXiv
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Main Authors: Fujimoto, Yuma, Ariu, Kaito, Abe, Kenshi
Format: Preprint
Published: 2024
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_version_ 1866915182618345472
author Fujimoto, Yuma
Ariu, Kaito
Abe, Kenshi
author_facet Fujimoto, Yuma
Ariu, Kaito
Abe, Kenshi
contents Learning in zero-sum games studies a situation where multiple agents competitively learn their strategy. In such multi-agent learning, we often see that the strategies cycle around their optimum, i.e., Nash equilibrium. When a game periodically varies (called a ``periodic'' game), however, the Nash equilibrium moves generically. How learning dynamics behave in such periodic games is of interest but still unclear. Interestingly, we discover that the behavior is highly dependent on the relationship between the two speeds at which the game changes and at which players learn. We observe that when these two speeds synchronize, the learning dynamics diverge, and their time-average does not converge. Otherwise, the learning dynamics draw complicated cycles, but their time-average converges. Under some assumptions introduced for the dynamical systems analysis, we prove that this behavior occurs. Furthermore, our experiments observe this behavior even if removing these assumptions. This study discovers a novel phenomenon, i.e., synchronization, and gains insight widely applicable to learning in periodic games.
format Preprint
id arxiv_https___arxiv_org_abs_2408_10595
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Synchronization in Learning in Periodic Zero-Sum Games Triggers Divergence from Nash Equilibrium
Fujimoto, Yuma
Ariu, Kaito
Abe, Kenshi
Computer Science and Game Theory
Multiagent Systems
Optimization and Control
Chaotic Dynamics
Learning in zero-sum games studies a situation where multiple agents competitively learn their strategy. In such multi-agent learning, we often see that the strategies cycle around their optimum, i.e., Nash equilibrium. When a game periodically varies (called a ``periodic'' game), however, the Nash equilibrium moves generically. How learning dynamics behave in such periodic games is of interest but still unclear. Interestingly, we discover that the behavior is highly dependent on the relationship between the two speeds at which the game changes and at which players learn. We observe that when these two speeds synchronize, the learning dynamics diverge, and their time-average does not converge. Otherwise, the learning dynamics draw complicated cycles, but their time-average converges. Under some assumptions introduced for the dynamical systems analysis, we prove that this behavior occurs. Furthermore, our experiments observe this behavior even if removing these assumptions. This study discovers a novel phenomenon, i.e., synchronization, and gains insight widely applicable to learning in periodic games.
title Synchronization in Learning in Periodic Zero-Sum Games Triggers Divergence from Nash Equilibrium
topic Computer Science and Game Theory
Multiagent Systems
Optimization and Control
Chaotic Dynamics
url https://arxiv.org/abs/2408.10595