On Connectedness of Solutions to Integer Linear Systems

Fuente: arXiv
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Autori principali: Shigenobu, Takasugu, Kamiyama, Naoyuki
Natura: Preprint
Pubblicazione: 2024
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author Shigenobu, Takasugu
Kamiyama, Naoyuki
author_facet Shigenobu, Takasugu
Kamiyama, Naoyuki
contents An integer linear system (ILS) is a linear system with integer constraints. The solution graph of an ILS is defined as an undirected graph defined on the set of feasible solutions to the ILS. A pair of feasible solutions is connected by an edge in the solution graph if the Hamming distance between them is 1. We consider a property of the coefficient matrix of an ILS such that the solution graph is connected for any right-hand side vector. Especially, we focus on the existence of an elimination ordering (EO) of a coefficient matrix, which is known as the sufficient condition for the connectedness of the solution graph for any right-hand side vector. That is, we consider the question whether the existence of an EO of the coefficient matrix is a necessary condition for the connectedness of the solution graph for any right-hand side vector. We first prove that if a coefficient matrix has at least four rows and at least three columns, then the existence of an EO may not be a necessary condition. Next, we prove that if a coefficient matrix has at most three rows or at most two columns, then the existence of an EO is a necessary condition.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19516
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Connectedness of Solutions to Integer Linear Systems
Shigenobu, Takasugu
Kamiyama, Naoyuki
Discrete Mathematics
An integer linear system (ILS) is a linear system with integer constraints. The solution graph of an ILS is defined as an undirected graph defined on the set of feasible solutions to the ILS. A pair of feasible solutions is connected by an edge in the solution graph if the Hamming distance between them is 1. We consider a property of the coefficient matrix of an ILS such that the solution graph is connected for any right-hand side vector. Especially, we focus on the existence of an elimination ordering (EO) of a coefficient matrix, which is known as the sufficient condition for the connectedness of the solution graph for any right-hand side vector. That is, we consider the question whether the existence of an EO of the coefficient matrix is a necessary condition for the connectedness of the solution graph for any right-hand side vector. We first prove that if a coefficient matrix has at least four rows and at least three columns, then the existence of an EO may not be a necessary condition. Next, we prove that if a coefficient matrix has at most three rows or at most two columns, then the existence of an EO is a necessary condition.
title On Connectedness of Solutions to Integer Linear Systems
topic Discrete Mathematics
url https://arxiv.org/abs/2411.19516