An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points

In this paper, we give examples that improve the lower bound on the maximum number of halving lines for sets in the plane with 35, 59, 95, and 97 points and, as a consequence, we improve the current best upper bound of the rectilinear crossing number for sets in the plane with 35, 59, 95, and 97 poi...

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Main Authors: Javier Rodrigo, Mariló López, Danilo Magistrali, Estrella Alonso
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Axioms
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Online Access:https://www.mdpi.com/2075-1680/14/1/62
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author Javier Rodrigo
Mariló López
Danilo Magistrali
Estrella Alonso
author_facet Javier Rodrigo
Mariló López
Danilo Magistrali
Estrella Alonso
author_sort Javier Rodrigo
collection DOAJ
description In this paper, we give examples that improve the lower bound on the maximum number of halving lines for sets in the plane with 35, 59, 95, and 97 points and, as a consequence, we improve the current best upper bound of the rectilinear crossing number for sets in the plane with 35, 59, 95, and 97 points, provided that a conjecture included in the literature is true. As another consequence, we also improve the lower bound on the maximum number of halving pseudolines for sets in the plane with 35 points. These examples, and the recursive bounds for the maximum number of halving lines for sets with an odd number of points achieved, give a new insight in the study of the rectilinear crossing number problem, one of the most challenging tasks in Discrete Geometry. With respect to this problem, it is conjectured that, for all <i>n</i> multiples of 3, there are 3-symmetric sets of <i>n</i> points for which the rectilinear crossing number is attained.
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publishDate 2025-01-01
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spelling doaj-art-d13bd0f37e2c4189b0c3f67c9ccf9ca32025-01-24T13:22:18ZengMDPI AGAxioms2075-16802025-01-011416210.3390/axioms14010062An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of PointsJavier Rodrigo0Mariló López1Danilo Magistrali2Estrella Alonso3Departamento de Matemática Aplicada, E.T.S. de Ingeniería, Universidad Pontificia Comillas de Madrid, 28015 Madrid, SpainDepartamento de Matemática e Informática Aplicadas a las Ingenierías Civil y Naval de la E.T.S.I. Caminos, Canales y Puertos, Universidad Politécnica de Madrid, 28040 Madrid, SpainDepartamento de Matemática Aplicada, E.T.S. de Ingeniería, Universidad Pontificia Comillas de Madrid, 28015 Madrid, SpainDepartamento de Matemática Aplicada, E.T.S. de Ingeniería, Universidad Pontificia Comillas de Madrid, 28015 Madrid, SpainIn this paper, we give examples that improve the lower bound on the maximum number of halving lines for sets in the plane with 35, 59, 95, and 97 points and, as a consequence, we improve the current best upper bound of the rectilinear crossing number for sets in the plane with 35, 59, 95, and 97 points, provided that a conjecture included in the literature is true. As another consequence, we also improve the lower bound on the maximum number of halving pseudolines for sets in the plane with 35 points. These examples, and the recursive bounds for the maximum number of halving lines for sets with an odd number of points achieved, give a new insight in the study of the rectilinear crossing number problem, one of the most challenging tasks in Discrete Geometry. With respect to this problem, it is conjectured that, for all <i>n</i> multiples of 3, there are 3-symmetric sets of <i>n</i> points for which the rectilinear crossing number is attained.https://www.mdpi.com/2075-1680/14/1/62discrete geometryhalving linesrectilinear crossing numberoptimization
spellingShingle Javier Rodrigo
Mariló López
Danilo Magistrali
Estrella Alonso
An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
Axioms
discrete geometry
halving lines
rectilinear crossing number
optimization
title An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
title_full An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
title_fullStr An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
title_full_unstemmed An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
title_short An Improvement of the Lower Bound on the Maximum Number of Halving Lines for Sets in the Plane with an Odd Number of Points
title_sort improvement of the lower bound on the maximum number of halving lines for sets in the plane with an odd number of points
topic discrete geometry
halving lines
rectilinear crossing number
optimization
url https://www.mdpi.com/2075-1680/14/1/62
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