Title
On the number of ordinary lines determined by sets in complex space.
Abstract
Kelly’s theorem states that a set of n points affinely spanning \({\mathbb {C}}^3\) must determine at least one ordinary complex line (a line incident to exactly two of the points). Our main theorem shows that such sets determine at least 3n / 2 ordinary lines, unless the configuration has \(n-1\) points in a plane and one point outside the plane (in which case there are at least \(n-1\) ordinary lines). In addition, when at most n / 2 points are contained in any plane, we prove stronger bounds that take advantage of the existence of lines with four or more points (in the spirit of Melchior’s and Hirzebruch’s inequalities). Furthermore, when the points span four or more dimensions, with at most n / 2 points contained in any three-dimensional affine subspace, we show that there must be a quadratic number of ordinary lines.
Year
DOI
Venue
2017
10.4230/LIPIcs.SoCG.2017.15
Symposium on Computational Geometry
Keywords
DocType
Volume
Ordinary lines, Sylvester–Gallai, Combinatorial geometry, Designs
Conference
abs/1611.08740
Issue
ISSN
Citations 
4
1432-0444
0
PageRank 
References 
Authors
0.34
0
4
Name
Order
Citations
PageRank
Abdul Basit13016.18
Zeev Dvir243730.85
Shubhangi Saraf326324.55
Charles Wolf400.34