Co-Exploration and Co-Exploitation via Shared Structure in Multi-Task Bandits

Fuente: arXiv
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Main Authors: Mukherjee, Sumantrak, Lebedeva, Serafima, Margraf, Valentin, Hanselle, Jonas, Yamaoka, Kanta, Bengs, Viktor, Konigorski, Stefan, Hüllermeier, Eyke, Vollmer, Sebastian Josef
Format: Preprint
Published: 2025
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author Mukherjee, Sumantrak
Lebedeva, Serafima
Margraf, Valentin
Hanselle, Jonas
Yamaoka, Kanta
Bengs, Viktor
Konigorski, Stefan
Hüllermeier, Eyke
Vollmer, Sebastian Josef
author_facet Mukherjee, Sumantrak
Lebedeva, Serafima
Margraf, Valentin
Hanselle, Jonas
Yamaoka, Kanta
Bengs, Viktor
Konigorski, Stefan
Hüllermeier, Eyke
Vollmer, Sebastian Josef
contents We propose a novel Bayesian framework for efficient exploration in contextual multi-task multi-armed bandit settings, where the context is only observed partially and dependencies between reward distributions are induced by latent context variables. In order to exploit these structural dependencies, our approach integrates observations across all tasks and learns a global joint distribution, while still allowing personalised inference for new tasks. In this regard, we identify two key sources of epistemic uncertainty, namely structural uncertainty in the latent reward dependencies across arms and tasks, and user-specific uncertainty due to incomplete context and limited interaction history. To put our method into practice, we represent the joint distribution over tasks and rewards using a particle-based approximation of a log-density Gaussian process. This representation enables flexible, data-driven discovery of both inter-arm and inter-task dependencies without prior assumptions on the latent variables. Empirically, we demonstrate that our method outperforms baselines such as hierarchical model bandits, especially in settings with model misspecification or complex latent heterogeneity.
format Preprint
id arxiv_https___arxiv_org_abs_2512_12693
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Co-Exploration and Co-Exploitation via Shared Structure in Multi-Task Bandits
Mukherjee, Sumantrak
Lebedeva, Serafima
Margraf, Valentin
Hanselle, Jonas
Yamaoka, Kanta
Bengs, Viktor
Konigorski, Stefan
Hüllermeier, Eyke
Vollmer, Sebastian Josef
Machine Learning
Artificial Intelligence
We propose a novel Bayesian framework for efficient exploration in contextual multi-task multi-armed bandit settings, where the context is only observed partially and dependencies between reward distributions are induced by latent context variables. In order to exploit these structural dependencies, our approach integrates observations across all tasks and learns a global joint distribution, while still allowing personalised inference for new tasks. In this regard, we identify two key sources of epistemic uncertainty, namely structural uncertainty in the latent reward dependencies across arms and tasks, and user-specific uncertainty due to incomplete context and limited interaction history. To put our method into practice, we represent the joint distribution over tasks and rewards using a particle-based approximation of a log-density Gaussian process. This representation enables flexible, data-driven discovery of both inter-arm and inter-task dependencies without prior assumptions on the latent variables. Empirically, we demonstrate that our method outperforms baselines such as hierarchical model bandits, especially in settings with model misspecification or complex latent heterogeneity.
title Co-Exploration and Co-Exploitation via Shared Structure in Multi-Task Bandits
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2512.12693