activity
20242026
collaborators

9 papers

stat.ML2026

On Regret Bounds of Thompson Sampling for Bayesian Optimization

Shion Takeno, Shogo Iwazaki

We study a widely used Bayesian optimization method, Gaussian process Thompson sampling (GP-TS), under the assumption that the objective function is a sample path from a GP. Compar…

cs.LG2026

Nearly-Optimal Algorithm for Adversarial Kernelized Bandits

Shogo Iwazaki

This paper studies kernelized bandits (also known as Gaussian process bandits) in an adversarial environment, where the reward functions in a known reproducing kernel Hilbert space…

cs.LG2026

Tighter Regret Lower Bound for Gaussian Process Bandits with Squared Exponential Kernel in Hypersphere

Shogo Iwazaki

We study an algorithm-independent, worst-case lower bound for the Gaussian process (GP) bandit problem in the frequentist setting, where the reward function is fixed and has a boun…

cs.LG2025

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

Shogo Iwazaki

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 und…

cs.LG2025

Gaussian Process Upper Confidence Bound Achieves Nearly-Optimal Regret in Noise-Free Gaussian Process Bandits

Shogo Iwazaki

We study the noise-free Gaussian Process (GP) bandits problem, in which the learner seeks to minimize regret through noise-free observations of the black-box objective function lyi…

stat.ML2025

High-dimensional Nonparametric Contextual Bandit Problem

Shogo Iwazaki, Junpei Komiyama, Masaaki Imaizumi

We consider the kernelized contextual bandit problem with a large feature space. This problem involves arms, and the goal of the forecaster is to maximize the cumulative reward…