Exact Algorithms for Distance to Unique Vertex Cover

Fuente: arXiv
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Main Authors: Fioravantes, Foivos, Knop, Dušan, Melissinos, Nikolaos, Opler, Michal, Vasilakis, Manolis
Format: Preprint
Published: 2025
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author Fioravantes, Foivos
Knop, Dušan
Melissinos, Nikolaos
Opler, Michal
Vasilakis, Manolis
author_facet Fioravantes, Foivos
Knop, Dušan
Melissinos, Nikolaos
Opler, Michal
Vasilakis, Manolis
contents Horiyama et al. (AAAI 2024) studied the problem of generating graph instances that possess a unique minimum vertex cover under specific conditions. Their approach involved pre-assigning certain vertices to be part of the solution or excluding them from it. Notably, for the \textsc{Vertex Cover} problem, pre-assigning a vertex is equivalent to removing it from the graph. Horiyama et al.~focused on maintaining the size of the minimum vertex cover after these modifications. In this work, we extend their study by relaxing this constraint: our goal is to ensure a unique minimum vertex cover, even if the removal of a vertex may not incur a decrease on the size of said cover. Surprisingly, our relaxation introduces significant theoretical challenges. We observe that the problem is $Σ^2_P$-complete, and remains so even for planar graphs of maximum degree 5. Nevertheless, we provide a linear time algorithm for trees, which is then further leveraged to show that MU-VC is in \textsf{FPT} when parameterized by the combination of treewidth and maximum degree. Finally, we show that MU-VC is in \textsf{XP} when parameterized by clique-width while it is fixed-parameter tractable (FPT) if we add the size of the solution as part of the parameter.
format Preprint
id arxiv_https___arxiv_org_abs_2502_05059
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exact Algorithms for Distance to Unique Vertex Cover
Fioravantes, Foivos
Knop, Dušan
Melissinos, Nikolaos
Opler, Michal
Vasilakis, Manolis
Data Structures and Algorithms
Computational Complexity
Horiyama et al. (AAAI 2024) studied the problem of generating graph instances that possess a unique minimum vertex cover under specific conditions. Their approach involved pre-assigning certain vertices to be part of the solution or excluding them from it. Notably, for the \textsc{Vertex Cover} problem, pre-assigning a vertex is equivalent to removing it from the graph. Horiyama et al.~focused on maintaining the size of the minimum vertex cover after these modifications. In this work, we extend their study by relaxing this constraint: our goal is to ensure a unique minimum vertex cover, even if the removal of a vertex may not incur a decrease on the size of said cover. Surprisingly, our relaxation introduces significant theoretical challenges. We observe that the problem is $Σ^2_P$-complete, and remains so even for planar graphs of maximum degree 5. Nevertheless, we provide a linear time algorithm for trees, which is then further leveraged to show that MU-VC is in \textsf{FPT} when parameterized by the combination of treewidth and maximum degree. Finally, we show that MU-VC is in \textsf{XP} when parameterized by clique-width while it is fixed-parameter tractable (FPT) if we add the size of the solution as part of the parameter.
title Exact Algorithms for Distance to Unique Vertex Cover
topic Data Structures and Algorithms
Computational Complexity
url https://arxiv.org/abs/2502.05059