AI & ML
Near-Optimal First-Order Regret for Bandits with Feedback Graphs
arXiv stat.ML0 views
arXiv:2610.40861v1 Announce Type: cross Abstract: We study first-order regret guarantees for adversarial bandits with a fixed, known directed feedback graph. For strongly observable graphs, [ACBDK15] establishes a minimax regret of $\widetilde{\Theta}(\sqrt{\alpha T})$, where $\alpha$ denotes the independence number of the graph and $T$ denotes the horizon. On the other hand, the best existing first-order bound scales as $\widetilde{O}(\sqrt{(\kappa+1) L^\star})$ [LLZ20], where $\kappa$ denotes the clique partition number, satisfying $\kappa+1\geq\alpha$, and $L^\star$ denotes the cumulative loss of the best arm, leaving a gap between the graph dependence in worst-case and first-order guarantees. In this paper, we bridge this gap by obtaining an expected regret bound of $\widetilde{O}(\sqrt{\alpha L^\star}+\alpha)$. Our first result is an algorithm for the special case of self-aware graphs, in which every vertex has a self-loop. The algorithm combines the update of EXP3 [ACBFS02] with a sampling rule inspired by exploration by optimization [LS20]. More specifically, we construct a map whose fixed points yield sampling distributions that control the one-round regret remainder in terms of the learner's loss and the graph's independence number, which is crucial in deriving optimal first-order guarantees. We further show that a sufficiently accurate fixed point can be computed in polynomial time by a geometrically convergent iteration. Finally, we extend the algorithm to general strongly observable graphs and achieve the same $\widetilde{O}(\sqrt{\alpha L^\star}+\alpha)$ guarantee by adapting the two-level aggregation approach of [LLZ20].
Source:https://arxiv.org/abs/2610.40861PreviousCertified Behavioral Retention for Continual Adaptation with Held-Out AnchorsNextDensity-Guided Bootstrap Boundaries for Latent World-Model Reinforcement Learning
Related posts

The Download: the agentic web arrives and the drive for safer roads
0MIT Technology Review

Stop counting tokens, start counting what ships
0MIT Technology Review
OpenAI is finally merging ChatGPT’s chat and Work tabs
0TechCrunch

10 Open-Source Robotics Repositories for 3D Perception, VLA Policies, and Sensor Calibration
0dev.to
My self-modifying system tried to wire a gate-passing module into its own protection enforcer. It was refused three times.
0dev.to
Last night an AI agent performed brain surgery on a mouse
0Hacker News