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arXiv · 1804.00335

Online learning with graph-structured feedback against adaptive adversaries

Zhili Feng·Po-Ling Loh
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Abstract

We derive upper and lower bounds for the policy regret of $T$-round online learning problems with graph-structured feedback, where the adversary is nonoblivious but assumed to have a bounded memory. We obtain upper bounds of $\widetilde O(T^{2/3})$ and $\widetilde O(T^{3/4})$ for strongly-observable and weakly-observable graphs, respectively, based on analyzing a variant of the Exp3 algorithm. When the adversary is allowed a bounded memory of size 1, we show that a matching lower bound of $\widetilde\Omega(T^{2/3})$ is achieved in the case of full-information feedback. We also study the particular loss structure of an oblivious adversary with switching costs, and show that in such a setting, non-revealing strongly-observable feedback graphs achieve a lower bound of $\widetilde\Omega(T^{2/3})$, as well.

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Zhili Feng, Po-Ling Loh. 2018-04-01. Online learning with graph-structured feedback against adaptive adversaries. https://arxiv.org/abs/1804.00335

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