arXiv Statistics ML

Model Predictive Control is almost Optimal for Heterogeneous Restless Multi-armed Bandits

arXiv Machine Learning
Jul 28

Finite-Time Analysis of the Natural Policy Gradient in Finite-Horizon Markov Decision Processes

arXiv:2607. 22982v1 Announce Type: new Abstract: Natural Policy Gradient (NPG) is a well-established Reinforcement Learning algorithm that underlies widely used methods such as Trust Region Policy Optimization and Proximal Policy Optimization, both of which have demonstrated strong empirical success.

By Asha Barua, Sajad Khodadadian
arXiv Statistics ML
Oct 2

Block Optimism for Nonstationary Bandits with Latent Linear Dynamics

The paper introduces a new algorithm for a nonstationary bandit setting where actions influence both immediate rewards and the evolution of an unobserved latent linear state. By approximating the infinite‑memory reward process with a finite‑memory block‑level proxy and applying a UCB‑based block algorithm, the authors achieve a regret bound of “~O(√T)”, improving upon the previous “~O(T^{2/3})” guarantee. This represents the first such “~O(√T)” result for latent linear‑dynamics bandits with bilinear rewards and an open‑loop action‑sequence benchmark.

By Taehyun Hwang, Hyunjun Choi, Heesang Ann, Min-hwan Oh
arXiv Machine Learning
3d ago

Transfer Learning in Bandits from Unknown Adaptive Policies: Problem-Dependent Lower and Upper Bounds

The paper investigates transfer learning in stochastic multi‑armed bandits when historical data come from an unknown adaptive policy. It establishes asymptotic problem‑dependent lower bounds and introduces the KL‑UCB‑Transfer algorithm, which combines online and historical data to achieve logarithmic regret with an improved constant under certain mean‑gap conditions. The study also relaxes the source‑target discrepancy assumption to a one‑sided condition, demonstrating that logarithmic regret can still be achieved under misspecification and identifying regimes of improvement, degradation, or loss of guarantee.

By Adrien Prevost, Timothee Mathieu, Waris Radji, Odalric-Ambrym Maillard