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We consider the best-arm identification problem in multi-armed bandits, which focuses purely on exploration. A player is given a fixed budget to explore a finite set of arms, and the rewards of each arm are drawn independently from a fixed,…

Machine Learning · Statistics 2017-08-02 Shahin Shahrampour , Mohammad Noshad , Vahid Tarokh

In a fixed-confidence pure exploration problem in stochastic multi-armed bandits, an algorithm iteratively samples arms and should stop as early as possible and return the correct answer to a query about the arms distributions. We are…

Machine Learning · Computer Science 2025-02-04 Adrienne Tuynman , Rémy Degenne

We consider the problem of near-optimal arm identification in the fixed confidence setting of the infinitely armed bandit problem when nothing is known about the arm reservoir distribution. We (1) introduce a PAC-like framework within which…

Machine Learning · Statistics 2018-05-22 Maryam Aziz , Jesse Anderton , Emilie Kaufmann , Javed Aslam

This paper investigates the problem of best arm identification in $\textit{contaminated}$ stochastic multi-arm bandits. In this setting, the rewards obtained from any arm are replaced by samples from an adversarial model with probability…

Machine Learning · Computer Science 2021-11-16 Arpan Mukherjee , Ali Tajer , Pin-Yu Chen , Payel Das

We consider a stochastic bandit problem with a possibly infinite number of arms. We write $p^*$ for the proportion of optimal arms and $\Delta$ for the minimal mean-gap between optimal and sub-optimal arms. We characterize the optimal…

Machine Learning · Computer Science 2021-11-08 Rianne de Heide , James Cheshire , Pierre Ménard , Alexandra Carpentier

We give a complete characterization of the complexity of best-arm identification in one-parameter bandit problems. We prove a new, tight lower bound on the sample complexity. We propose the `Track-and-Stop' strategy, which we prove to be…

Statistics Theory · Mathematics 2016-06-02 Aurélien Garivier , Emilie Kaufmann

We study the fixed-confidence best arm identification (BAI) problem within the multi-armed bandit (MAB) framework under the Entropic Value-at-Risk (EVaR) criterion. Our analysis considers a nonparametric setting, allowing for general reward…

Machine Learning · Computer Science 2025-10-07 Mehrasa Ahmadipour , Aurélien Garivier

We study best arm identification in a variant of the multi-armed bandit problem where the learner has limited precision in arm selection. The learner can only sample arms via certain exploration bundles, which we refer to as boxes. In…

Machine Learning · Computer Science 2023-05-11 Kota Srinivas Reddy , P. N. Karthik , Nikhil Karamchandani , Jayakrishnan Nair

We consider the problem of \textit{best arm identification} with a \textit{fixed budget $T$}, in the $K$-armed stochastic bandit setting, with arms distribution defined on $[0,1]$. We prove that any bandit strategy, for at least one bandit…

Machine Learning · Statistics 2016-05-31 Alexandra Carpentier , Andrea Locatelli

We address the problem of identifying the optimal policy with a fixed confidence level in a multi-armed bandit setup, when \emph{the arms are subject to linear constraints}. Unlike the standard best-arm identification problem which is well…

Machine Learning · Computer Science 2024-01-26 Emil Carlsson , Debabrota Basu , Fredrik D. Johansson , Devdatt Dubhashi

We consider the problem of identifying any $k$ out of the best $m$ arms in an $n$-armed stochastic multi-armed bandit. Framed in the PAC setting, this particular problem generalises both the problem of `best subset selection' and that of…

Machine Learning · Computer Science 2019-01-25 Arghya Roy Chaudhuri , Shivaram Kalyanakrishnan

In fixed budget bandit identification, an algorithm sequentially observes samples from several distributions up to a given final time. It then answers a query about the set of distributions. A good algorithm will have a small probability of…

Machine Learning · Statistics 2023-07-03 Rémy Degenne

In multi-armed bandits, the tasks of reward maximization and pure exploration are often at odds with each other. The former focuses on exploiting arms with the highest means, while the latter may require constant exploration across all…

Machine Learning · Computer Science 2024-10-22 Brian Cho , Dominik Meier , Kyra Gan , Nathan Kallus

We study an identification problem in multi-armed bandits. In each round a learner selects one of $K$ arms and observes its reward, with the goal of eventually identifying an arm that will perform best at a {\it future} time. In adversarial…

Machine Learning · Computer Science 2026-03-03 Nataly Brukhim , Nicolò Cesa-Bianchi , Carlo Ciliberto

We consider the Max $K$-Armed Bandit problem, where a learning agent is faced with several sources (arms) of items (rewards), and interested in finding the best item overall. At each time step the agent chooses an arm, and obtains a random…

Machine Learning · Statistics 2015-08-25 Yahel David , Nahum Shimkin

We consider best arm identification in the multi-armed bandit problem. Assuming certain continuity conditions of the prior, we characterize the rate of the Bayesian simple regret. Differing from Bayesian regret minimization (Lai, 1987), the…

Machine Learning · Computer Science 2023-07-27 Junpei Komiyama , Kaito Ariu , Masahiro Kato , Chao Qin

Recently multi-armed bandit problem arises in many real-life scenarios where arms must be sampled in batches, due to limited time the agent can wait for the feedback. Such applications include biological experimentation and online…

Machine Learning · Statistics 2023-12-22 Shengyu Cao , Simai He , Ruoqing Jiang , Jin Xu , Hongsong Yuan

The pure-exploration problem in stochastic multi-armed bandits aims to find one or more arms with the largest (or near largest) means. Examples include finding an {\epsilon}-good arm, best-arm identification, top-k arm identification, and…

Machine Learning · Statistics 2020-09-14 Blake Mason , Lalit Jain , Ardhendu Tripathy , Robert Nowak

In this paper we consider the problem of best-arm identification in multi-armed bandits in the fixed confidence setting, where the goal is to identify, with probability $1-\delta$ for some $\delta>0$, the arm with the highest mean reward in…

Machine Learning · Statistics 2021-09-13 Samarth Gupta , Gauri Joshi , Osman Yağan

We consider a variant of the best arm identification task in stochastic multi-armed bandits. Motivated by risk-averse decision-making problems, our goal is to identify a set of $m$ arms with the highest $\tau$-quantile values within a fixed…

Machine Learning · Computer Science 2023-02-22 Mengyan Zhang , Cheng Soon Ong