Noncrossing Longest Paths and Cycles

Fuente: arXiv
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Main Authors: Aloupis, Greg, Biniaz, Ahmad, Bose, Prosenjit, De Carufel, Jean-Lou, Eppstein, David, Maheshwari, Anil, Odak, Saeed, Smid, Michiel, Tóth, Csaba D., Valtr, Pavel
Format: Preprint
Published: 2024
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author Aloupis, Greg
Biniaz, Ahmad
Bose, Prosenjit
De Carufel, Jean-Lou
Eppstein, David
Maheshwari, Anil
Odak, Saeed
Smid, Michiel
Tóth, Csaba D.
Valtr, Pavel
author_facet Aloupis, Greg
Biniaz, Ahmad
Bose, Prosenjit
De Carufel, Jean-Lou
Eppstein, David
Maheshwari, Anil
Odak, Saeed
Smid, Michiel
Tóth, Csaba D.
Valtr, Pavel
contents Edge crossings in geometric graphs are sometimes undesirable as they could lead to unwanted situations such as collisions in motion planning and inconsistency in VLSI layout. Short geometric structures such as shortest perfect matchings, shortest spanning trees, shortest spanning paths, and shortest spanning cycles on a given point set are inherently noncrossing. However, the longest such structures need not be noncrossing. In fact, it is intuitive to expect many edge crossings in various geometric graphs that are longest. Recently, Álvarez-Rebollar, Cravioto-Lagos, Marín, Solé-Pi, and Urrutia (Graphs and Combinatorics, 2024) constructed a set of points for which the longest perfect matching is noncrossing. They raised several challenging questions in this direction. In particular, they asked whether the longest spanning path, on any finite set of points in the plane, must have a pair of crossing edges. They also conjectured that the longest spanning cycle must have a pair of crossing edges. In this paper, we give a negative answer to the question and also refute the conjecture. We present a framework for constructing arbitrarily large point sets for which the longest perfect matchings, the longest spanning paths, and the longest spanning cycles are noncrossing.
format Preprint
id arxiv_https___arxiv_org_abs_2410_05580
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Noncrossing Longest Paths and Cycles
Aloupis, Greg
Biniaz, Ahmad
Bose, Prosenjit
De Carufel, Jean-Lou
Eppstein, David
Maheshwari, Anil
Odak, Saeed
Smid, Michiel
Tóth, Csaba D.
Valtr, Pavel
Computational Geometry
Edge crossings in geometric graphs are sometimes undesirable as they could lead to unwanted situations such as collisions in motion planning and inconsistency in VLSI layout. Short geometric structures such as shortest perfect matchings, shortest spanning trees, shortest spanning paths, and shortest spanning cycles on a given point set are inherently noncrossing. However, the longest such structures need not be noncrossing. In fact, it is intuitive to expect many edge crossings in various geometric graphs that are longest. Recently, Álvarez-Rebollar, Cravioto-Lagos, Marín, Solé-Pi, and Urrutia (Graphs and Combinatorics, 2024) constructed a set of points for which the longest perfect matching is noncrossing. They raised several challenging questions in this direction. In particular, they asked whether the longest spanning path, on any finite set of points in the plane, must have a pair of crossing edges. They also conjectured that the longest spanning cycle must have a pair of crossing edges. In this paper, we give a negative answer to the question and also refute the conjecture. We present a framework for constructing arbitrarily large point sets for which the longest perfect matchings, the longest spanning paths, and the longest spanning cycles are noncrossing.
title Noncrossing Longest Paths and Cycles
topic Computational Geometry
url https://arxiv.org/abs/2410.05580