2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57719This article gives a detailed presentation of the authors' recent results on the ground state properties of the Bose gas. It is a much expanded version of a talk given by one of the authors (E.H.L.) at the conference "Perspectives in Analysis" at the KTH, Stockholm, June 23, 2003. It is based on, but supersedes, the article math-ph/0204027.AMSLaTeX, 86 pages; minor modifications, typos correctedMathematical Physicstext