Smoothed Analysis of Online Metric Matching with a Single Sample: Beyond Metric Distortion

Fuente: arXiv
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Autori principali: Li, Yingxi, Vitercik, Ellen, Yang, Mingwei
Natura: Preprint
Pubblicazione: 2025
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author Li, Yingxi
Vitercik, Ellen
Yang, Mingwei
author_facet Li, Yingxi
Vitercik, Ellen
Yang, Mingwei
contents In the online metric matching problem, $n$ servers and $n$ requests lie in a metric space. Servers are available upfront, and requests arrive sequentially. An arriving request must be matched immediately and irrevocably to an available server, incurring a cost equal to their distance. The goal is to minimize the total matching cost. We study this problem in the Euclidean metric $[0, 1]^d$, when servers are adversarial and requests are independently drawn from distinct distributions that satisfy a mild smoothness condition. Our main result is an $O(1)$-competitive algorithm for $d \neq 2$ that requires no distributional knowledge, relying only on a single sample from each request distribution. To our knowledge, this is the first algorithm to achieve an $o(\log n)$ competitive ratio for non-trivial metrics beyond the i.i.d. setting. Our approach bypasses the $Ω(\log n)$ barrier introduced by probabilistic metric embeddings: instead of analyzing the embedding distortion and the algorithm separately, we directly bound the cost of the algorithm on the target metric of a simple deterministic embedding. We then combine this analysis with lower bounds on the offline optimum for Euclidean metrics, derived via majorization arguments, to obtain our guarantees.
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id arxiv_https___arxiv_org_abs_2510_20288
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publishDate 2025
record_format arxiv
spellingShingle Smoothed Analysis of Online Metric Matching with a Single Sample: Beyond Metric Distortion
Li, Yingxi
Vitercik, Ellen
Yang, Mingwei
Data Structures and Algorithms
In the online metric matching problem, $n$ servers and $n$ requests lie in a metric space. Servers are available upfront, and requests arrive sequentially. An arriving request must be matched immediately and irrevocably to an available server, incurring a cost equal to their distance. The goal is to minimize the total matching cost. We study this problem in the Euclidean metric $[0, 1]^d$, when servers are adversarial and requests are independently drawn from distinct distributions that satisfy a mild smoothness condition. Our main result is an $O(1)$-competitive algorithm for $d \neq 2$ that requires no distributional knowledge, relying only on a single sample from each request distribution. To our knowledge, this is the first algorithm to achieve an $o(\log n)$ competitive ratio for non-trivial metrics beyond the i.i.d. setting. Our approach bypasses the $Ω(\log n)$ barrier introduced by probabilistic metric embeddings: instead of analyzing the embedding distortion and the algorithm separately, we directly bound the cost of the algorithm on the target metric of a simple deterministic embedding. We then combine this analysis with lower bounds on the offline optimum for Euclidean metrics, derived via majorization arguments, to obtain our guarantees.
title Smoothed Analysis of Online Metric Matching with a Single Sample: Beyond Metric Distortion
topic Data Structures and Algorithms
url https://arxiv.org/abs/2510.20288