arXiv:2604.25271stat.MLcs.LG2026-04被引 19

在随机观测损失的老虎机问题中,提出两种算法实现近最优后悔界。

Online learning with Erdős-Rényi side-observation graphs

  • 基于独立随机观测机制设计自适应算法
  • 当观测概率r≥logT/(2N)时,后悔上界为O(√(T/r logN))
  • 适用于观测概率未知且低的情况,适合在线学习研究者

我们研究对抗性多臂老虎机问题,其中学习者在选择一个动作后,可随机观测未选中动作的损失。所有非选中臂以固定但未知的概率 $r$ 独立揭示其损失。针对不同 $r$ 范围,提出两种算法:第一种在 $r \geq \log T / (2N)$ 时,$T$ 轮内期望后悔为 $O(\sqrt{(T / r) \log N})$;第二种在更小 $r$ 下,达到 $O(\sqrt{(T / r) \log (N + T)})$。还提供快速估计 $r$ 范围的方法。所有界均与已知 $r$ 的最优算法仅差对数因子。

原文摘要 · Abstract (English)

We consider adversarial multi-armed bandit problems where the learner is allowed to observe losses of a number of arms beside the arm that it actually chose. We study the case where all non-chosen arms reveal their loss with a fixed but unknown probability $r$, independently of each other and the action of the learner. We propose two algorithms that work for different ranges of $r$. We show that after $T$ rounds in a bandit problem with $N$ arms, the expected regret of our first algorithm is $O(\sqrt{(T /r) \log N })$ whenever $r\ge(\log T)/(2N)$, while our second algorithm achieves a regret of $O(\sqrt{(T/r) \log (N+T)})$ for smaller values of $r$. We also give a quick estimation procedure that decides the range of~$r$. All our bounds are within logarithmic factors of the best achievable performance of any algorithm that is even allowed to know~$r$.

在线学习多臂老虎机随机观测后悔界

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