2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/62439The sphere packing problem asks for the densest packing of unit balls in d-dimensional Euclidean space. This problem has its roots in geometry, number theory and it is part of Hilbert's 18th problem. In 1958 C. A. Rogers proved a non-trivial upper bound for the density of unit ball packings in d-dimensional Euclidean space for all d>0. In 1978 Kabatjanskii and Levenstein improved this bound for large d. In fact, Rogers' bound is the presently known best bound for 43>d>3, and above that the Kabatjanskii-Levenstein bound takes over. In this paper we improve Rogers' upper bound for the density of unit ball packings in Euclidean d-space for all d>7. We do this by estimating from below the surface area of Voronoi cells in any packing of unit balls in Euclidean d-space for all d>7.to be published in Discrete and Comput. GeomMetric Geometry52C17 (Primary) 52A40 (Secondary)text