Better Approximation for Weighted $k$-Matroid Intersection

Fuente: arXiv
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Main Authors: Singer, Neta, Thiery, Theophile
Format: Preprint
Published: 2024
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author Singer, Neta
Thiery, Theophile
author_facet Singer, Neta
Thiery, Theophile
contents We consider the problem of finding an independent set of maximum weight simultaneously contained in $k$ matroids over a common ground set. This $k$-matroid intersection problem appears naturally in many contexts, for example in generalizing graph and hypergraph matching problems. In this paper, we provide a $(k+1)/(2 \ln 2)$-approximation algorithm for the weighted $k$-matroid intersection problem. This is the first improvement over the longstanding $(k-1)$-guarantee of Lee, Sviridenko and Vondrák (2009). Along the way, we also give the first improvement over greedy for the more general weighted matroid $k$-parity problem. Our key innovation lies in a randomized reduction in which we solve almost unweighted instances iteratively. This perspective allows us to use insights from the unweighted problem for which Lee, Sviridenko, and Vondrák have designed a $k/2$-approximation algorithm. We analyze this procedure by constructing refined matroid exchanges and leveraging randomness to avoid bad local minima.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19366
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Better Approximation for Weighted $k$-Matroid Intersection
Singer, Neta
Thiery, Theophile
Data Structures and Algorithms
Discrete Mathematics
F.2.2; G.1.6
We consider the problem of finding an independent set of maximum weight simultaneously contained in $k$ matroids over a common ground set. This $k$-matroid intersection problem appears naturally in many contexts, for example in generalizing graph and hypergraph matching problems. In this paper, we provide a $(k+1)/(2 \ln 2)$-approximation algorithm for the weighted $k$-matroid intersection problem. This is the first improvement over the longstanding $(k-1)$-guarantee of Lee, Sviridenko and Vondrák (2009). Along the way, we also give the first improvement over greedy for the more general weighted matroid $k$-parity problem. Our key innovation lies in a randomized reduction in which we solve almost unweighted instances iteratively. This perspective allows us to use insights from the unweighted problem for which Lee, Sviridenko, and Vondrák have designed a $k/2$-approximation algorithm. We analyze this procedure by constructing refined matroid exchanges and leveraging randomness to avoid bad local minima.
title Better Approximation for Weighted $k$-Matroid Intersection
topic Data Structures and Algorithms
Discrete Mathematics
F.2.2; G.1.6
url https://arxiv.org/abs/2411.19366