2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/72281We study the fixed point set in the ideal boundary of a parabolic isometry of a proper CAT(0)-space. We show that the radius of the fixed point set is at most pi/2, and study its centers. As a consequence, we prove that the set of fixed points is contractible with respect to the Tits topology.29 pagesDifferential GeometryMetric Geometry53C20text