A tight example for approximation ratio 5 for covering small cuts by the primal-dual method

Fuente: arXiv
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Main Author: Nutov, Zeev
Format: Preprint
Published: 2025
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author Nutov, Zeev
author_facet Nutov, Zeev
contents In the Small Cuts Cover problem we seek to cover by a min-cost edge-set the set family of cuts of size/capacity $<k$ of a graph. Recently, Simmons showed that the primal-dual algorithm of Williamson, Goemans, Mihail, and Vazirani achieves approximation ratio $5$ for this problem, and asked whether this bound is tight. We will answer this question positively, by providing an example in which the ratio between the solution produced by the primal-dual algorithm and the optimum is arbitrarily close to $5$.
format Preprint
id arxiv_https___arxiv_org_abs_2512_08350
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A tight example for approximation ratio 5 for covering small cuts by the primal-dual method
Nutov, Zeev
Data Structures and Algorithms
In the Small Cuts Cover problem we seek to cover by a min-cost edge-set the set family of cuts of size/capacity $<k$ of a graph. Recently, Simmons showed that the primal-dual algorithm of Williamson, Goemans, Mihail, and Vazirani achieves approximation ratio $5$ for this problem, and asked whether this bound is tight. We will answer this question positively, by providing an example in which the ratio between the solution produced by the primal-dual algorithm and the optimum is arbitrarily close to $5$.
title A tight example for approximation ratio 5 for covering small cuts by the primal-dual method
topic Data Structures and Algorithms
url https://arxiv.org/abs/2512.08350