More Benefits of Being Distributional: Second-Order Bounds for Reinforcement Learning

Fuente: arXiv
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Main Authors: Wang, Kaiwen, Oertell, Owen, Agarwal, Alekh, Kallus, Nathan, Sun, Wen
Format: Preprint
Published: 2024
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author Wang, Kaiwen
Oertell, Owen
Agarwal, Alekh
Kallus, Nathan
Sun, Wen
author_facet Wang, Kaiwen
Oertell, Owen
Agarwal, Alekh
Kallus, Nathan
Sun, Wen
contents In this paper, we prove that Distributional Reinforcement Learning (DistRL), which learns the return distribution, can obtain second-order bounds in both online and offline RL in general settings with function approximation. Second-order bounds are instance-dependent bounds that scale with the variance of return, which we prove are tighter than the previously known small-loss bounds of distributional RL. To the best of our knowledge, our results are the first second-order bounds for low-rank MDPs and for offline RL. When specializing to contextual bandits (one-step RL problem), we show that a distributional learning based optimism algorithm achieves a second-order worst-case regret bound, and a second-order gap dependent bound, simultaneously. We also empirically demonstrate the benefit of DistRL in contextual bandits on real-world datasets. We highlight that our analysis with DistRL is relatively simple, follows the general framework of optimism in the face of uncertainty and does not require weighted regression. Our results suggest that DistRL is a promising framework for obtaining second-order bounds in general RL settings, thus further reinforcing the benefits of DistRL.
format Preprint
id arxiv_https___arxiv_org_abs_2402_07198
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle More Benefits of Being Distributional: Second-Order Bounds for Reinforcement Learning
Wang, Kaiwen
Oertell, Owen
Agarwal, Alekh
Kallus, Nathan
Sun, Wen
Machine Learning
In this paper, we prove that Distributional Reinforcement Learning (DistRL), which learns the return distribution, can obtain second-order bounds in both online and offline RL in general settings with function approximation. Second-order bounds are instance-dependent bounds that scale with the variance of return, which we prove are tighter than the previously known small-loss bounds of distributional RL. To the best of our knowledge, our results are the first second-order bounds for low-rank MDPs and for offline RL. When specializing to contextual bandits (one-step RL problem), we show that a distributional learning based optimism algorithm achieves a second-order worst-case regret bound, and a second-order gap dependent bound, simultaneously. We also empirically demonstrate the benefit of DistRL in contextual bandits on real-world datasets. We highlight that our analysis with DistRL is relatively simple, follows the general framework of optimism in the face of uncertainty and does not require weighted regression. Our results suggest that DistRL is a promising framework for obtaining second-order bounds in general RL settings, thus further reinforcing the benefits of DistRL.
title More Benefits of Being Distributional: Second-Order Bounds for Reinforcement Learning
topic Machine Learning
url https://arxiv.org/abs/2402.07198