A column generation algorithm for finding co-3-plexes in chordal graphs

Fuente: arXiv
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Main Author: Dupont-Bouillard, Alexandre
Format: Preprint
Published: 2026
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author Dupont-Bouillard, Alexandre
author_facet Dupont-Bouillard, Alexandre
contents In this study, we tackle the problem of finding a maximum \emph{co-3-plex}, which is a subset of vertices of an input graph, inducing a subgraph of maximum degree 2. We focus on the class of chordal graphs. By observing that the graph induced by a co-3-plex in a chordal graph is a set of isolated triangles and induced paths, we reduce the problem of finding a maximum weight co-3-plex in a graph $G$ to that of finding a maximum stable set in an auxiliary graph $\mathcal{A}(G)$ of exponential size. This reduction allows us to derive an exponential variable-sized linear programming formulation for the maximum weighted co-3-plex problem. We show that the pricing subproblem of this formulation reduces to solving a maximum vertex and edge weight induced path. Such a problem is solvable in polynomial time; therefore, this exhibits a polynomial time column generation algorithm solving the maximum co-3-plex problem on chordal graphs. Moreover, this machinery exhibits a new application for the maximum vertex and edge weighted induced path problems.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00721
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A column generation algorithm for finding co-3-plexes in chordal graphs
Dupont-Bouillard, Alexandre
Data Structures and Algorithms
Discrete Mathematics
In this study, we tackle the problem of finding a maximum \emph{co-3-plex}, which is a subset of vertices of an input graph, inducing a subgraph of maximum degree 2. We focus on the class of chordal graphs. By observing that the graph induced by a co-3-plex in a chordal graph is a set of isolated triangles and induced paths, we reduce the problem of finding a maximum weight co-3-plex in a graph $G$ to that of finding a maximum stable set in an auxiliary graph $\mathcal{A}(G)$ of exponential size. This reduction allows us to derive an exponential variable-sized linear programming formulation for the maximum weighted co-3-plex problem. We show that the pricing subproblem of this formulation reduces to solving a maximum vertex and edge weight induced path. Such a problem is solvable in polynomial time; therefore, this exhibits a polynomial time column generation algorithm solving the maximum co-3-plex problem on chordal graphs. Moreover, this machinery exhibits a new application for the maximum vertex and edge weighted induced path problems.
title A column generation algorithm for finding co-3-plexes in chordal graphs
topic Data Structures and Algorithms
Discrete Mathematics
url https://arxiv.org/abs/2604.00721