arXiv Machine Learning

The Sample Complexity of Multiple Change Point Identification under Bandit Feedback

arXiv Machine Learning
Oct 8

Best Arm Identification for Bandits with Shifting Means

arXiv:2610. 10488v1 Announce Type: cross Abstract: We study the best arm identification problem in a stochastic environment with a novel form of adversarial perturbations, which we coin Shifting Means.

By Lukas Zierahn, Wouter M. Koolen, Shubhada Agrawal, Christina Katsimerou, Dirk van der Hoeven
arXiv Machine Learning
19h ago

The Price of Current-Effect Inference in Nonstationary Multi-Armed Bandits

The paper studies the trade‑off between maximizing rewards and accurately estimating current treatment effects in nonstationary multi‑armed bandits. For $K$‑armed bandits with H"older‑smooth mean rewards, the authors derive minimax bounds on expected dynamic regret under a high‑probability simultaneous coverage requirement for all current effects. They propose the TRACE algorithm, which achieves a regret–precision trade‑off that separates reward‑learning regret from the unavoidable cost of refreshing current‑effect estimates, and extend the method with an empirical‑Bernstein e‑process to adapt exploration while preserving worst‑case guarantees.

By Sharan Sahu, Martin T. Wells
arXiv Machine Learning
Jun 19

Indexed Bellman Information Complexity

arXiv:2606. 11171v2 Announce Type: replace Abstract: We develop indexed Bellman information complexity, a representation-level theory of interactive decision making centered on information indices and reference histories.

By Yunbei Xu
arXiv AI
Oct 15

Rethinking Langevin Thompson Sampling from A Stochastic Approximation Perspective

The paper introduces TS-SA, a variant of Langevin-based Thompson Sampling that integrates stochastic approximation into the bandit framework. TS-SA performs a single Langevin step per new reward and updates a persistent Markov chain for each arm, avoiding repeated sampling of past data. This approach yields a near‑optimal worst‑case regret bound of ≥O(√{KT}) under log‑concavity and smoothness, and empirical results show strong performance against standard baselines.

By Weixin Wang, Haoyang Zheng, Guang Lin, Wei Deng, Pan Xu