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Bandits with Side Observations: Bounded vs. Logarithmic Regret
Proceedings of the 34th Conference on Uncertainty in Artificial Intelligence, PMLR R16:466-475, 2018.
Abstract
We consider the classical stochastic multi- armed bandit but where, from time to time and roughly with frequency $\epsilon$, an extra observation is gathered by the agent for free. We prove that, no matter how small $\epsilon$ is the agent can ensure a regret uniformly bounded in time. More precisely, we construct an algorithm with a regret smaller than P i log(1/$\epsilon$) $\Delta$i , up to multi- plicative constant and log log terms. We also prove a matching lower-bound, stating that no reasonable algorithm can outperform this quantity.