Learning to Sparsify Stochastic Linear Bandits

Fuente: arXiv
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Autori principali: Wang, Zhengmiao, Chi, Ming, Liu, Zhi-Wei, Ye, Lintao, Chiasserini, Carla Fabiana
Natura: Preprint
Pubblicazione: 2026
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author Wang, Zhengmiao
Chi, Ming
Liu, Zhi-Wei
Ye, Lintao
Chiasserini, Carla Fabiana
author_facet Wang, Zhengmiao
Chi, Ming
Liu, Zhi-Wei
Ye, Lintao
Chiasserini, Carla Fabiana
contents This paper addresses the problem of learning to sparsify stochastic linear bandits, where a decision-maker sequentially selects actions from a high-dimensional space subject to a sparsity constraint on the number of nonzero elements in the action vector. The key challenge lies in minimizing cumulative regret while tackling the potential NP-hardness of finding optimal sparse actions due to the inherent combinatorial structure of the problem. We propose an adaptively phased exploration and exploitation algorithmic framework, utilizing ordinary least squares for parameter learning and specialized subroutines for sparse action selection. When the action set is a Euclidean ball, optimal sparse actions can be efficiently computed, enabling us to establish a $\tilde{\mathcal{O}}(d\sqrt{T})$ regret, where $d$ is the dimension of the action vector and $T$ is the time horizon length. For general convex and compact action sets where finding optimal sparse actions is intractable, we employ a greedy subroutine. For general strongly convex action sets, we derive a $\tilde{\mathcal{O}}(d \sqrt{T})$ $α$-regret; for general compact sets lacking strong convexity, we establish a $\tilde{\mathcal{O}}(d T^{2/3})$ $α$-regret, where $α$ pertains to the approximation ratio of the greedy algorithm. Finally, we validate the performance of our algorithms using extensive experiments including an application to recommendation system.
format Preprint
id arxiv_https___arxiv_org_abs_2605_10151
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Learning to Sparsify Stochastic Linear Bandits
Wang, Zhengmiao
Chi, Ming
Liu, Zhi-Wei
Ye, Lintao
Chiasserini, Carla Fabiana
Machine Learning
Systems and Control
Optimization and Control
This paper addresses the problem of learning to sparsify stochastic linear bandits, where a decision-maker sequentially selects actions from a high-dimensional space subject to a sparsity constraint on the number of nonzero elements in the action vector. The key challenge lies in minimizing cumulative regret while tackling the potential NP-hardness of finding optimal sparse actions due to the inherent combinatorial structure of the problem. We propose an adaptively phased exploration and exploitation algorithmic framework, utilizing ordinary least squares for parameter learning and specialized subroutines for sparse action selection. When the action set is a Euclidean ball, optimal sparse actions can be efficiently computed, enabling us to establish a $\tilde{\mathcal{O}}(d\sqrt{T})$ regret, where $d$ is the dimension of the action vector and $T$ is the time horizon length. For general convex and compact action sets where finding optimal sparse actions is intractable, we employ a greedy subroutine. For general strongly convex action sets, we derive a $\tilde{\mathcal{O}}(d \sqrt{T})$ $α$-regret; for general compact sets lacking strong convexity, we establish a $\tilde{\mathcal{O}}(d T^{2/3})$ $α$-regret, where $α$ pertains to the approximation ratio of the greedy algorithm. Finally, we validate the performance of our algorithms using extensive experiments including an application to recommendation system.
title Learning to Sparsify Stochastic Linear Bandits
topic Machine Learning
Systems and Control
Optimization and Control
url https://arxiv.org/abs/2605.10151