Dual Representation of Minimum Divergence Under Integral Constraints

Fuente: arXiv
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Main Authors: Shekhar, Shubhanshu, Agrawal, Shubhada
Format: Preprint
Published: 2026
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author Shekhar, Shubhanshu
Agrawal, Shubhada
author_facet Shekhar, Shubhanshu
Agrawal, Shubhada
contents Minimum divergence problems under integral constraints appear throughout statistics and probability, including sequential inference, bandit theory, and distributionally robust optimization. In many such settings, dual representations are the key step that convert information-theoretic lower bounds into computationally tractable (and often near-optimal) algorithms. In this paper, we present a general two-stage recipe for deriving dual representations of constrained minimum divergence (in the second argument) for distributions supported on $[0,1]^K$. The first stage derives a dual representation for finitely-supported distributions using classical finite-dimensional convex duality techniques, while the second establishes an abstract interchange argument that lifts this discretized dual to arbitrary distributions. We begin with the simplest case of mean-constrained minimum relative entropy, commonly called $\mathrm{KL}_{\inf}$, and generalize an existing argument from multi-armed bandits literature for $K=1$ to arbitrary dimensions. Our main contribution is to significantly expand the scope of this approach to a broad class of $f$-divergences (beyond relative entropy) and to general integral constraint functionals (beyond the mean constraint). Finally, we illustrate the statistical implications of our results by constructing optimal procedures for sequential testing, estimation, and change detection with observations in $[0,1]^K$.
format Preprint
id arxiv_https___arxiv_org_abs_2603_21027
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dual Representation of Minimum Divergence Under Integral Constraints
Shekhar, Shubhanshu
Agrawal, Shubhada
Information Theory
Statistics Theory
Minimum divergence problems under integral constraints appear throughout statistics and probability, including sequential inference, bandit theory, and distributionally robust optimization. In many such settings, dual representations are the key step that convert information-theoretic lower bounds into computationally tractable (and often near-optimal) algorithms. In this paper, we present a general two-stage recipe for deriving dual representations of constrained minimum divergence (in the second argument) for distributions supported on $[0,1]^K$. The first stage derives a dual representation for finitely-supported distributions using classical finite-dimensional convex duality techniques, while the second establishes an abstract interchange argument that lifts this discretized dual to arbitrary distributions. We begin with the simplest case of mean-constrained minimum relative entropy, commonly called $\mathrm{KL}_{\inf}$, and generalize an existing argument from multi-armed bandits literature for $K=1$ to arbitrary dimensions. Our main contribution is to significantly expand the scope of this approach to a broad class of $f$-divergences (beyond relative entropy) and to general integral constraint functionals (beyond the mean constraint). Finally, we illustrate the statistical implications of our results by constructing optimal procedures for sequential testing, estimation, and change detection with observations in $[0,1]^K$.
title Dual Representation of Minimum Divergence Under Integral Constraints
topic Information Theory
Statistics Theory
url https://arxiv.org/abs/2603.21027