On crossing-families in planar point sets

被引:2
|
作者
Aichholzer, Oswin [1 ]
Kyncl, Jan [2 ]
Scheucher, Manfred [3 ]
Vogtenhuber, Birgit [1 ]
Valtr, Pavel [2 ]
机构
[1] Graz Univ Technol, Inst Software Technol, Graz, Austria
[2] Charles Univ Prague, Fac Math & Phys, Dept Appl Math, Prague, Czech Republic
[3] Tech Univ Berlin, Inst Math, Berlin, Germany
基金
奥地利科学基金会;
关键词
Crossing family; Point set; Order type; Geometric thrackle;
D O I
10.1016/j.comgeo.2022.101899
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
A k-crossing family in a point set S in general position is a set of k segments spanned by points of S such that all k segments mutually cross. In this short note we present two statements on crossing families which are based on sets of small cardinality: (1) Any set of at least 15 points contains a crossing family of size 4. (2) There are sets of n points which do not contain a crossing family of size larger than 8 inverted right perpendicular pi/4inverted left perpendicular. Both results improve the previously best known bounds. (C) 2022 Elsevier B.V. All rights reserved.
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页数:8
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