Covering spheres with spheres

Abstract

Given a sphere of any radius $r$ in an $n$-dimensional Euclidean space, we study the coverings of this sphere with solid spheres of radius one. Our goal is to design a covering of the lowest covering density, which defines the average number of solid spheres covering a point in a bigger sphere. For a growing dimension $n,$ we design a covering that has covering density of order $(n\ln n)/2$ for the full Euclidean space or for a sphere of any radius $r>1.$ This new upper bound reduces two times the asymptotic order of $n\ln n$ established in the classical Rogers bound.