MathDB
504 points on a unit disc, from any 5 points we can choose 2 with distance <=1

Source: JBMO Shortlist 2015 C2

April 24, 2019
combinatoricscombinatorial geometrypointsdistance

Problem Statement

20152015 points are given in a plane such that from any five points we can choose two points with distance less than 11 unit. Prove that 504504 of the given points lie on a unit disc.