Bayesian Best-Arm Identification with Abstention: A Polynomial-to-Exponential Phase Transition

arXiv:2606.29203v1 Announce Type: new Abstract: We study the Bayesian fixed-budget best-arm identification problem in which a learner can abstain from making a terminal recommendation. Subject to an abstention budget $\alpha$, we analyze the probability of undetected error--the risk of recommending a suboptimal arm without abstaining. Our central finding is that abstention induces a phase transition: without abstention, the error probability decays polynomially in the sampling budget $T$; in contrast, introducing any small positive abstention budget shifts this to an exponential decay. For Gau
This academic paper from arXiv is published as part of the ongoing research output in the field of artificial intelligence and machine learning, particularly concerning Bayesian optimization techniques.
While technically interesting for AI researchers, this specific finding on Bayesian best-arm identification with abstention has limited immediate strategic implications for a broad institutional audience.
This paper refines theoretical understanding within a niche area of machine learning, but it does not fundamentally alter the landscape of AI development, deployment, or its broader societal impact.
Refined theoretical understanding for researchers working on multi-armed bandit problems and sequential decision-making under uncertainty.
Potential for improved algorithmic efficiency or robustness in specific real-world applications that heavily rely on Bayesian optimization with abstention, though this is not a general breakthrough.
Very long-term, highly theoretical contributions like this might incrementally contribute to more reliable and ethical AI systems, but its direct path to impact is limited.
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