Near-optimal Regret Using Policy Optimization in Online MDPs with Aggregate Bandit Feedback

Fuente: arXiv
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Main Authors: Lancewicki, Tal, Mansour, Yishay
Format: Preprint
Published: 2025
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author Lancewicki, Tal
Mansour, Yishay
author_facet Lancewicki, Tal
Mansour, Yishay
contents We study online finite-horizon Markov Decision Processes with adversarially changing loss and aggregate bandit feedback (a.k.a full-bandit). Under this type of feedback, the agent observes only the total loss incurred over the entire trajectory, rather than the individual losses at each intermediate step within the trajectory. We introduce the first Policy Optimization algorithms for this setting. In the known-dynamics case, we achieve the first \textit{optimal} regret bound of $\tilde Θ(H^2\sqrt{SAK})$, where $K$ is the number of episodes, $H$ is the episode horizon, $S$ is the number of states, and $A$ is the number of actions. In the unknown dynamics case we establish regret bound of $\tilde O(H^3 S \sqrt{AK})$, significantly improving the best known result by a factor of $H^2 S^5 A^2$.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04004
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Near-optimal Regret Using Policy Optimization in Online MDPs with Aggregate Bandit Feedback
Lancewicki, Tal
Mansour, Yishay
Machine Learning
We study online finite-horizon Markov Decision Processes with adversarially changing loss and aggregate bandit feedback (a.k.a full-bandit). Under this type of feedback, the agent observes only the total loss incurred over the entire trajectory, rather than the individual losses at each intermediate step within the trajectory. We introduce the first Policy Optimization algorithms for this setting. In the known-dynamics case, we achieve the first \textit{optimal} regret bound of $\tilde Θ(H^2\sqrt{SAK})$, where $K$ is the number of episodes, $H$ is the episode horizon, $S$ is the number of states, and $A$ is the number of actions. In the unknown dynamics case we establish regret bound of $\tilde O(H^3 S \sqrt{AK})$, significantly improving the best known result by a factor of $H^2 S^5 A^2$.
title Near-optimal Regret Using Policy Optimization in Online MDPs with Aggregate Bandit Feedback
topic Machine Learning
url https://arxiv.org/abs/2502.04004