Improved Regret Bounds for Gaussian Process Upper Confidence Bound in Bayesian Optimization

Fuente: arXiv
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Main Author: Iwazaki, Shogo
Format: Preprint
Published: 2025
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author Iwazaki, Shogo
author_facet Iwazaki, Shogo
contents This paper addresses the Bayesian optimization problem (also referred to as the Bayesian setting of the Gaussian process bandit), where the learner seeks to minimize the regret under a function drawn from a known Gaussian process (GP). Under a Matérn kernel with a certain degree of smoothness, we show that the Gaussian process upper confidence bound (GP-UCB) algorithm achieves $\tilde{O}(\sqrt{T})$ cumulative regret with high probability. Furthermore, our analysis yields $O(\sqrt{T \ln^2 T})$ regret under a squared exponential kernel. These results fill the gap between the existing regret upper bound for GP-UCB and the best-known bound provided by Scarlett (2018). The key idea in our proof is to capture the concentration behavior of the input sequence realized by GP-UCB, enabling a more refined analysis of the GP's information gain.
format Preprint
id arxiv_https___arxiv_org_abs_2506_01393
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Improved Regret Bounds for Gaussian Process Upper Confidence Bound in Bayesian Optimization
Iwazaki, Shogo
Machine Learning
This paper addresses the Bayesian optimization problem (also referred to as the Bayesian setting of the Gaussian process bandit), where the learner seeks to minimize the regret under a function drawn from a known Gaussian process (GP). Under a Matérn kernel with a certain degree of smoothness, we show that the Gaussian process upper confidence bound (GP-UCB) algorithm achieves $\tilde{O}(\sqrt{T})$ cumulative regret with high probability. Furthermore, our analysis yields $O(\sqrt{T \ln^2 T})$ regret under a squared exponential kernel. These results fill the gap between the existing regret upper bound for GP-UCB and the best-known bound provided by Scarlett (2018). The key idea in our proof is to capture the concentration behavior of the input sequence realized by GP-UCB, enabling a more refined analysis of the GP's information gain.
title Improved Regret Bounds for Gaussian Process Upper Confidence Bound in Bayesian Optimization
topic Machine Learning
url https://arxiv.org/abs/2506.01393