A Lower Bound on the Density of Sphere Packings via Graph Theory

Krivelevich, Michael; Litsyn, Simon; Vardy, Alexander

A Lower Bound on the Density of Sphere Packings via Graph Theory

Authors

Krivelevich, Michael

Litsyn, Simon

Vardy, Alexander

Description

Using graph-theoretic methods we give a new proof that for all sufficiently large $n$, there exist sphere packings in $\R^n$ of density at least $cn2^{-n}$, exceeding the classical Minkowski bound by a factor linear in $n$. This matches up to a constant the best known lower bounds on the density of sphere packings due to Rogers, Davenport-Rogers, and Ball. The suggested method makes it possible to describe the points of such a packing with complexity $\exp(n\log n)$, which is significantly lower than in the other approaches.
6 pages, 2 postscript figures