English

Counting large distances in convex polygons

Combinatorics 2011-08-01 v2 Computational Geometry

Abstract

In a convex n-gon, let d[1] > d[2] > ... denote the set of all distances between pairs of vertices, and let m[i] be the number of pairs of vertices at distance d[i] from one another. Erdos, Lovasz, and Vesztergombi conjectured that m[1] + ... + m[k] <= k*n. Using a new computational approach, we prove their conjecture when k <= 4 and n is large; we also make some progress for arbitrary k by proving that m[1] + ... + m[k] <= (2k-1)n. Our main approach revolves around a few known facts about distances, together with a computer program that searches all distance configurations of two disjoint convex hull intervals up to some finite size. We thereby obtain other new bounds such as m[3] <= 3n/2 for large n.

Keywords

Cite

@article{arxiv.1103.0412,
  title  = {Counting large distances in convex polygons},
  author = {Filip Morić and David Pritchard},
  journal= {arXiv preprint arXiv:1103.0412},
  year   = {2011}
}

Comments

Shorter version presented at EuroComb 2011

R2 v1 2026-06-21T17:34:10.757Z