Efficient Robust Constrained Signal Detection via Kolmogorov Width Approximations

Fuente: arXiv
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Main Authors: Li, Yikun, Neykov, Matey
Format: Preprint
Published: 2026
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author Li, Yikun
Neykov, Matey
author_facet Li, Yikun
Neykov, Matey
contents Robust statistical inference often faces a severe computational-statistical gap when dealing with complex parameter spaces. We investigate minimax signal detection in the Gaussian sequence model under strong $ε$-contamination, where the signal belongs to a general prior constraint $K$. Existing optimal tests require computing the exact Kolmogorov $k$-width of $K$, a computationally intractable task for general non-trivial sets. We bridge this gap by proposing a polynomial-time testing framework that universally applies to balanced, type-2, and exactly 2-convex constraints. By leveraging a semidefinite programming relaxation and a modified ellipsoid method equipped with an approximate subgradient oracle, we efficiently approximate the Kolmogorov widths. Remarkably, our unconditional efficient algorithm achieves a robust detection boundary that matches existing upper bounds up to a mere polylogarithmic factor. This establishes a computationally tractable testing solution for a broad class of structured signals without requiring prior knowledge of their exact geometric complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2605_11238
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Efficient Robust Constrained Signal Detection via Kolmogorov Width Approximations
Li, Yikun
Neykov, Matey
Statistics Theory
Computation
Robust statistical inference often faces a severe computational-statistical gap when dealing with complex parameter spaces. We investigate minimax signal detection in the Gaussian sequence model under strong $ε$-contamination, where the signal belongs to a general prior constraint $K$. Existing optimal tests require computing the exact Kolmogorov $k$-width of $K$, a computationally intractable task for general non-trivial sets. We bridge this gap by proposing a polynomial-time testing framework that universally applies to balanced, type-2, and exactly 2-convex constraints. By leveraging a semidefinite programming relaxation and a modified ellipsoid method equipped with an approximate subgradient oracle, we efficiently approximate the Kolmogorov widths. Remarkably, our unconditional efficient algorithm achieves a robust detection boundary that matches existing upper bounds up to a mere polylogarithmic factor. This establishes a computationally tractable testing solution for a broad class of structured signals without requiring prior knowledge of their exact geometric complexity.
title Efficient Robust Constrained Signal Detection via Kolmogorov Width Approximations
topic Statistics Theory
Computation
url https://arxiv.org/abs/2605.11238