Asymptotic and Finite Sample Analysis of Nonexpansive Stochastic Approximations with Markovian Noise

Fuente: arXiv
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Main Authors: Blaser, Ethan, Zhang, Shangtong
Format: Preprint
Published: 2024
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author Blaser, Ethan
Zhang, Shangtong
author_facet Blaser, Ethan
Zhang, Shangtong
contents Stochastic approximation is a powerful class of algorithms with celebrated success. However, a large body of previous analysis focuses on stochastic approximations driven by contractive operators, which is not applicable in some important reinforcement learning settings like the average reward setting. This work instead investigates stochastic approximations with merely nonexpansive operators. In particular, we study nonexpansive stochastic approximations with Markovian noise, providing both asymptotic and finite sample analysis. Key to our analysis are novel bounds of noise terms resulting from the Poisson equation. As an application, we prove for the first time that classical tabular average reward temporal difference learning converges to a sample-path dependent fixed point.
format Preprint
id arxiv_https___arxiv_org_abs_2409_19546
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Asymptotic and Finite Sample Analysis of Nonexpansive Stochastic Approximations with Markovian Noise
Blaser, Ethan
Zhang, Shangtong
Machine Learning
Artificial Intelligence
Optimization and Control
Stochastic approximation is a powerful class of algorithms with celebrated success. However, a large body of previous analysis focuses on stochastic approximations driven by contractive operators, which is not applicable in some important reinforcement learning settings like the average reward setting. This work instead investigates stochastic approximations with merely nonexpansive operators. In particular, we study nonexpansive stochastic approximations with Markovian noise, providing both asymptotic and finite sample analysis. Key to our analysis are novel bounds of noise terms resulting from the Poisson equation. As an application, we prove for the first time that classical tabular average reward temporal difference learning converges to a sample-path dependent fixed point.
title Asymptotic and Finite Sample Analysis of Nonexpansive Stochastic Approximations with Markovian Noise
topic Machine Learning
Artificial Intelligence
Optimization and Control
url https://arxiv.org/abs/2409.19546