MathDB
Uniform colorings of a polygon

Source: Kvant Magazine No. 1 2020, 50th Anniversary, M818

March 10, 2023
combinatoricsColoringKvant

Problem Statement

Some kk{} vertices of a regular nn{}-gon are colored red. We will call a coloring uniform if for any mm the number of red vertices in any two sets of mm consecutive vertices of the nn{}-gon coincide or differ by 1. Prove that a uniform coloring exists for any k<nk<n and is unique, up to rotations of the nn{}-gon.
Proposed by M. Kontsevich