2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/225003We determine the Stiefel-Whitney classes of the second exterior representation and the spin representation of Spin(15), which are useful to calculate the mod 2 cohomology of the classifying space of the exceptional Lie group E_8.This is the version published by Geometry & Topology Monographs on 14 November 2007Algebraic Topology55R40, 22E46text