2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66097A basic point about hyperbolic groups is that they have "spaces at infinity" which are spaces of homogeneous type in the sense of Coifman and Weiss, and with a lot of self-similarity coming from the group. This short survey deals with some of the notions involved.10 pages, latex-2e. Some additions to text and bibliographyClassical Analysis and ODEstext