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Related papers: Pareto Optimal Model Selection in Linear Bandits

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We introduce the problem of model selection for contextual bandits, where a learner must adapt to the complexity of the optimal policy while balancing exploration and exploitation. Our main result is a new model selection guarantee for…

Machine Learning · Computer Science 2019-11-15 Dylan J. Foster , Akshay Krishnamurthy , Haipeng Luo

We introduce the model selection problem in pure exploration linear bandits, where the learner needs to adapt to the instance-dependent complexity measure of the smallest hypothesis class containing the true model. We design algorithms in…

Machine Learning · Statistics 2022-03-18 Yinglun Zhu , Julian Katz-Samuels , Robert Nowak

We study bandit model selection in stochastic environments. Our approach relies on a meta-algorithm that selects between candidate base algorithms. We develop a meta-algorithm-base algorithm abstraction that can work with general classes of…

Machine Learning · Computer Science 2022-12-06 Aldo Pacchiano , My Phan , Yasin Abbasi-Yadkori , Anup Rao , Julian Zimmert , Tor Lattimore , Csaba Szepesvari

Model selection in contextual bandits is an important complementary problem to regret minimization with respect to a fixed model class. We consider the simplest non-trivial instance of model-selection: distinguishing a simple multi-armed…

Machine Learning · Computer Science 2022-07-01 Vidya Muthukumar , Akshay Krishnamurthy

We consider model selection in stochastic bandit and reinforcement learning problems. Given a set of base learning algorithms, an effective model selection strategy adapts to the best learning algorithm in an online fashion. We show that by…

Machine Learning · Computer Science 2020-06-11 Yasin Abbasi-Yadkori , Aldo Pacchiano , My Phan

This paper addresses the problem of learning to sparsify stochastic linear bandits, where a decision-maker sequentially selects actions from a high-dimensional space subject to a sparsity constraint on the number of nonzero elements in the…

Machine Learning · Computer Science 2026-05-12 Zhengmiao Wang , Ming Chi , Zhi-Wei Liu , Lintao Ye , Carla Fabiana Chiasserini

In this work, we investigate the problem of adapting to the presence or absence of causal structure in multi-armed bandit problems. In addition to the usual reward signal, we assume the learner has access to additional variables, observed…

Machine Learning · Computer Science 2024-07-02 Ziyi Liu , Idan Attias , Daniel M. Roy

We consider linear stochastic bandits where the set of actions is an ellipsoid. We provide the first known minimax optimal algorithm for this problem. We first derive a novel information-theoretic lower bound on the regret of any algorithm,…

Machine Learning · Statistics 2025-02-25 Raymond Zhang , Hedi Hadiji , Richard Combes

We study Pareto optimality in multi-objective multi-armed bandit by providing a formulation of adversarial multi-objective multi-armed bandit and defining its Pareto regrets that can be applied to both stochastic and adversarial settings.…

Machine Learning · Computer Science 2023-06-01 Mengfan Xu , Diego Klabjan

Multi-objective bandits have attracted increasing attention for their broad applicability, with \(d\)-dimensional reward vectors inducing Pareto regret. There has been a subtle debate over whether this added structure makes the problem…

Machine Learning · Computer Science 2026-05-08 Changkun Guan , Mengfan Xu

We study the multi-objective linear contextual bandit problem, where multiple possible conflicting objectives must be optimized simultaneously. We propose \texttt{MOL-TS}, the \textit{first} Thompson Sampling algorithm with Pareto regret…

Machine Learning · Statistics 2025-12-02 Somangchan Park , Heesang Ann , Min-hwan Oh

Motivated by practical needs such as large-scale learning, we study the impact of adaptivity constraints to linear contextual bandits, a central problem in online active learning. We consider two popular limited adaptivity models in…

Machine Learning · Computer Science 2021-04-26 Yufei Ruan , Jiaqi Yang , Yuan Zhou

We consider the well-studied dueling bandit problem, where a learner aims to identify near-optimal actions using pairwise comparisons, under the constraint of differential privacy. We consider a general class of utility-based preference…

Machine Learning · Computer Science 2024-03-25 Aadirupa Saha , Hilal Asi

Online model selection in Bayesian bandits raises a fundamental exploration challenge: When an environment instance is sampled from a prior distribution, how can we design an adaptive strategy that explores multiple bandit learners and…

Machine Learning · Computer Science 2026-02-23 Aida Afshar , Yuke Zhang , Aldo Pacchiano

We study stochastic linear optimization problem with bandit feedback. The set of arms take values in an $N$-dimensional space and belong to a bounded polyhedron described by finitely many linear inequalities. We provide a lower bound for…

Machine Learning · Computer Science 2015-09-29 Manjesh K. Hanawal , Amir Leshem , Venkatesh Saligrama

We provide the first algorithm for online bandit linear optimization whose regret after T rounds is of order sqrt{Td ln N} on any finite class X of N actions in d dimensions, and of order d*sqrt{T} (up to log factors) when X is infinite.…

Machine Learning · Computer Science 2012-02-15 Nicolò Cesa-Bianchi , Sham Kakade

We consider the problem of contextual bandits and imitation learning, where the learner lacks direct knowledge of the executed action's reward. Instead, the learner can actively query an expert at each round to compare two actions and…

Machine Learning · Computer Science 2023-07-25 Ayush Sekhari , Karthik Sridharan , Wen Sun , Runzhe Wu

We present a non-asymptotic lower bound on the eigenspectrum of the design matrix generated by any linear bandit algorithm with sub-linear regret when the action set has well-behaved curvature. Specifically, we show that the minimum…

Machine Learning · Computer Science 2023-01-10 Debangshu Banerjee , Avishek Ghosh , Sayak Ray Chowdhury , Aditya Gopalan

We propose a simple model selection approach for algorithms in stochastic bandit and reinforcement learning problems. As opposed to prior work that (implicitly) assumes knowledge of the optimal regret, we only require that each base…

Machine Learning · Computer Science 2020-12-25 Aldo Pacchiano , Christoph Dann , Claudio Gentile , Peter Bartlett

We study two model selection settings in stochastic linear bandits (LB). In the first setting, which we refer to as feature selection, the expected reward of the LB problem is in the linear span of at least one of $M$ feature maps (models).…

Machine Learning · Computer Science 2022-06-20 Ahmadreza Moradipari , Berkay Turan , Yasin Abbasi-Yadkori , Mahnoosh Alizadeh , Mohammad Ghavamzadeh
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