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Related papers: Conditionally Risk-Averse Contextual Bandits

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We study nonparametric contextual bandits under batch constraints, where the expected reward for each action is modeled as a smooth function of covariates, and the policy updates are made at the end of each batch of observations. We…

Statistics Theory · Mathematics 2025-10-06 Rong Jiang , Cong Ma

In this paper, we address the stochastic contextual linear bandit problem, where a decision maker is provided a context (a random set of actions drawn from a distribution). The expected reward of each action is specified by the inner…

Machine Learning · Statistics 2023-05-30 Osama A. Hanna , Lin F. Yang , Christina Fragouli

Contextual bandit algorithms are at the core of many applications, including recommender systems, clinical trials, and optimal portfolio selection. One of the most popular problems studied in the contextual bandit literature is to maximize…

Machine Learning · Computer Science 2023-10-24 Siddhant Chaudhary , Abhishek Sinha

Stochastic linear contextual bandit algorithms have substantial applications in practice, such as recommender systems, online advertising, clinical trials, etc. Recent works show that optimal bandit algorithms are vulnerable to adversarial…

Machine Learning · Statistics 2023-01-31 Qin Ding , Cho-Jui Hsieh , James Sharpnack

Contextual bandits are widely used in Internet services from news recommendation to advertising, and to Web search. Generalized linear models (logistical regression in particular) have demonstrated stronger performance than linear models in…

Machine Learning · Computer Science 2017-06-20 Lihong Li , Yu Lu , Dengyong Zhou

Contextual bandits serve as a fundamental model for many sequential decision making tasks. The most popular theoretically justified approaches are based on the optimism principle. While these algorithms can be practical, they are known to…

Machine Learning · Computer Science 2020-03-17 Botao Hao , Tor Lattimore , Csaba Szepesvari

In this paper, we investigate the impact of context diversity on stochastic linear contextual bandits. As opposed to the previous view that contexts lead to more difficult bandit learning, we show that when the contexts are sufficiently…

Machine Learning · Computer Science 2020-03-06 Weiqiang Wu , Jing Yang , Cong Shen

A contextual bandit problem is studied in a highly non-stationary environment, which is ubiquitous in various recommender systems due to the time-varying interests of users. Two models with disjoint and hybrid payoffs are considered to…

Machine Learning · Computer Science 2020-03-03 Xiao Xu , Fang Dong , Yanghua Li , Shaojian He , Xin Li

Contextual bandits have the same exploration-exploitation trade-off as standard multi-armed bandits. On adding positive externalities that decay with time, this problem becomes much more difficult as wrong decisions at the start are hard to…

Machine Learning · Computer Science 2019-11-15 Harsh Deshpande , Vishal Jain , Sharayu Moharir

Contextual bandit algorithms are essential for solving real-world decision making problems. In practice, collecting a contextual bandit's feedback from different domains may involve different costs. For example, measuring drug reaction from…

Machine Learning · Computer Science 2025-04-08 Ziyan Wang , Xiaoming Huo , Hao Wang

Bandits with covariates, a.k.a. contextual bandits, address situations where optimal actions (or arms) at a given time $t$, depend on a context $x_t$, e.g., a new patient's medical history, a consumer's past purchases. While it is…

Machine Learning · Statistics 2021-02-23 Joseph Suk , Samory Kpotufe

Contextual bandit algorithms are commonly used in digital health to recommend personalized treatments. However, to ensure the effectiveness of the treatments, patients are often requested to take actions that have no immediate benefit to…

Machine Learning · Computer Science 2024-03-14 Kyra Gan , Esmaeil Keyvanshokooh , Xueqing Liu , Susan Murphy

Multi-armed bandit algorithms have become a reference solution for handling the explore/exploit dilemma in recommender systems, and many other important real-world problems, such as display advertisement. However, such algorithms usually…

Machine Learning · Computer Science 2018-05-25 Qingyun Wu , Naveen Iyer , Hongning Wang

Contextual bandit algorithms are sensitive to the estimation method of the outcome model as well as the exploration method used, particularly in the presence of rich heterogeneity or complex outcome models, which can lead to difficult…

Machine Learning · Statistics 2018-12-18 Maria Dimakopoulou , Zhengyuan Zhou , Susan Athey , Guido Imbens

Contextual Multi-Armed Bandits is a well-known and accepted online optimization algorithm, that is used in many Web experiences to tailor content or presentation to users' traffic. Much has been published on theoretical guarantees (e.g.…

Information Retrieval · Computer Science 2019-07-12 David Abensur , Ivan Balashov , Shaked Bar , Ronny Lempel , Nurit Moscovici , Ilan Orlov , Danny Rosenstein , Ido Tamir

We study the problem of stochastic contextual bandits in the agnostic setting, where the goal is to compete with the best policy in a given class without assuming realizability or imposing model restrictions on losses or rewards. In this…

Machine Learning · Statistics 2026-04-06 Samuel Girard , Aurelien Bibaut , Arthur Gretton , Nathan Kallus , Houssam Zenati

We consider the contextual bandit problem on general action and context spaces, where the learner's rewards depend on their selected actions and an observable context. This generalizes the standard multi-armed bandit to the case where side…

Machine Learning · Statistics 2023-01-03 Moise Blanchard , Steve Hanneke , Patrick Jaillet

A fundamental challenge in contextual bandits is to develop flexible, general-purpose algorithms with computational requirements no worse than classical supervised learning tasks such as classification and regression. Algorithms based on…

Machine Learning · Computer Science 2020-06-24 Dylan J. Foster , Alexander Rakhlin

For infinite action contextual bandits, smoothed regret and reduction to regression results in state-of-the-art online performance with computational cost independent of the action set: unfortunately, the resulting data exhaust does not…

Machine Learning · Computer Science 2023-06-09 Mark Rucker , Yinglun Zhu , Paul Mineiro

We address the problem of learning in an online, bandit setting where the learner must repeatedly select among $K$ actions, but only receives partial feedback based on its choices. We establish two new facts: First, using a new algorithm…

Machine Learning · Computer Science 2011-10-28 Alina Beygelzimer , John Langford , Lihong Li , Lev Reyzin , Robert E. Schapire