2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/225013In this paper, we show that Singer's fifth transfer is not an epimorphism in degree 11. More precisely, it does not detect the element P(h_2) in Ext_A^{5,16}(F_2,F_2).This is the version published by Geometry & Topology Monographs on 14 November 2007Algebraic Topology55P47, 55Q45, 55S10, 55T15text