Exact Algorithms for Clustered Planarity with Linear Saturators

Fuente: arXiv
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Main Authors: Da Lozzo, Giordano, Ganian, Robert, Gupta, Siddharth, Mohar, Bojan, Ordyniak, Sebastian, Zehavi, Meirav
Format: Preprint
Published: 2024
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author Da Lozzo, Giordano
Ganian, Robert
Gupta, Siddharth
Mohar, Bojan
Ordyniak, Sebastian
Zehavi, Meirav
author_facet Da Lozzo, Giordano
Ganian, Robert
Gupta, Siddharth
Mohar, Bojan
Ordyniak, Sebastian
Zehavi, Meirav
contents We study Clustered Planarity with Linear Saturators, which is the problem of augmenting an $n$-vertex planar graph whose vertices are partitioned into independent sets (called clusters) with paths - one for each cluster - that connect all the vertices in each cluster while maintaining planarity. We show that the problem can be solved in time $2^{O(n)}$ for both the variable and fixed embedding case. Moreover, we show that it can be solved in subexponential time $2^{O(\sqrt{n}\log n)}$ in the fixed embedding case if additionally the input graph is connected. The latter time complexity is tight under the Exponential-Time Hypothesis. We also show that $n$ can be replaced with the vertex cover number of the input graph by providing a linear (resp. polynomial) kernel for the variable-embedding (resp. fixed-embedding) case; these results contrast the NP-hardness of the problem on graphs of bounded treewidth (and even on trees). Finally, we complement known lower bounds for the problem by showing that Clustered Planarity with Linear Saturators is NP-hard even when the number of clusters is at most $3$, thus excluding the algorithmic use of the number of clusters as a parameter.
format Preprint
id arxiv_https___arxiv_org_abs_2409_19410
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exact Algorithms for Clustered Planarity with Linear Saturators
Da Lozzo, Giordano
Ganian, Robert
Gupta, Siddharth
Mohar, Bojan
Ordyniak, Sebastian
Zehavi, Meirav
Data Structures and Algorithms
Computational Geometry
We study Clustered Planarity with Linear Saturators, which is the problem of augmenting an $n$-vertex planar graph whose vertices are partitioned into independent sets (called clusters) with paths - one for each cluster - that connect all the vertices in each cluster while maintaining planarity. We show that the problem can be solved in time $2^{O(n)}$ for both the variable and fixed embedding case. Moreover, we show that it can be solved in subexponential time $2^{O(\sqrt{n}\log n)}$ in the fixed embedding case if additionally the input graph is connected. The latter time complexity is tight under the Exponential-Time Hypothesis. We also show that $n$ can be replaced with the vertex cover number of the input graph by providing a linear (resp. polynomial) kernel for the variable-embedding (resp. fixed-embedding) case; these results contrast the NP-hardness of the problem on graphs of bounded treewidth (and even on trees). Finally, we complement known lower bounds for the problem by showing that Clustered Planarity with Linear Saturators is NP-hard even when the number of clusters is at most $3$, thus excluding the algorithmic use of the number of clusters as a parameter.
title Exact Algorithms for Clustered Planarity with Linear Saturators
topic Data Structures and Algorithms
Computational Geometry
url https://arxiv.org/abs/2409.19410