Bipartizing (Pseudo-)Disk Graphs: Approximation with a Ratio Better than 3

Fuente: arXiv
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Auteurs principaux: Lokshtanov, Daniel, Panolan, Fahad, Saurabh, Saket, Xue, Jie, Zehavi, Meirav
Format: Preprint
Publié: 2024
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author Lokshtanov, Daniel
Panolan, Fahad
Saurabh, Saket
Xue, Jie
Zehavi, Meirav
author_facet Lokshtanov, Daniel
Panolan, Fahad
Saurabh, Saket
Xue, Jie
Zehavi, Meirav
contents In a disk graph, every vertex corresponds to a disk in $\mathbb{R}^2$ and two vertices are connected by an edge whenever the two corresponding disks intersect. Disk graphs form an important class of geometric intersection graphs, which generalizes both planar graphs and unit-disk graphs. We study a fundamental optimization problem in algorithmic graph theory, Bipartization (also known as Odd Cycle Transversal), on the class of disk graphs. The goal of Bipartization is to delete a minimum number of vertices from the input graph such that the resulting graph is bipartite. A folklore (polynomial-time) $3$-approximation algorithm for Bipartization on disk graphs follows from the classical framework of Goemans and Williamson [Combinatorica'98] for cycle-hitting problems. For over two decades, this result has remained the best known approximation for the problem (in fact, even for Bipartization on unit-disk graphs). In this paper, we achieve the first improvement upon this result, by giving a $(3-α)$-approximation algorithm for Bipartization on disk graphs, for some constant $α>0$. Our algorithm directly generalizes to the broader class of pseudo-disk graphs. Furthermore, our algorithm is robust in the sense that it does not require a geometric realization of the input graph to be given.
format Preprint
id arxiv_https___arxiv_org_abs_2407_09356
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bipartizing (Pseudo-)Disk Graphs: Approximation with a Ratio Better than 3
Lokshtanov, Daniel
Panolan, Fahad
Saurabh, Saket
Xue, Jie
Zehavi, Meirav
Data Structures and Algorithms
Computational Geometry
In a disk graph, every vertex corresponds to a disk in $\mathbb{R}^2$ and two vertices are connected by an edge whenever the two corresponding disks intersect. Disk graphs form an important class of geometric intersection graphs, which generalizes both planar graphs and unit-disk graphs. We study a fundamental optimization problem in algorithmic graph theory, Bipartization (also known as Odd Cycle Transversal), on the class of disk graphs. The goal of Bipartization is to delete a minimum number of vertices from the input graph such that the resulting graph is bipartite. A folklore (polynomial-time) $3$-approximation algorithm for Bipartization on disk graphs follows from the classical framework of Goemans and Williamson [Combinatorica'98] for cycle-hitting problems. For over two decades, this result has remained the best known approximation for the problem (in fact, even for Bipartization on unit-disk graphs). In this paper, we achieve the first improvement upon this result, by giving a $(3-α)$-approximation algorithm for Bipartization on disk graphs, for some constant $α>0$. Our algorithm directly generalizes to the broader class of pseudo-disk graphs. Furthermore, our algorithm is robust in the sense that it does not require a geometric realization of the input graph to be given.
title Bipartizing (Pseudo-)Disk Graphs: Approximation with a Ratio Better than 3
topic Data Structures and Algorithms
Computational Geometry
url https://arxiv.org/abs/2407.09356