2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77381It is proved that an arbitrary finite group acting locally linearly, homologically trivially, and pseudofreely on a closed, simply connected 4-manifold must in fact be cyclic and act semifreely, provided the second betti number of the manifold is at least three.14 pagesGeometric Topology57M60; 57S17; 20J06text