2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/165609We describe the integral cohomology rings of the flag manifolds of types B_n, D_n, G_2 and F_4 in terms of their Schubert classes. The main tool is the divided difference operators of Bernstein-Gelfand-Gelfand and Demazure. As an application, we compute the Chow rings of the corresponding complex algebraic groups, recovering thereby the results of R. Marlin.25 pages, AMS-LaTeX; typos corrected, an error concerning the Schubert classes corrected, Remarks 4.4 and 4.8 addedAlgebraic TopologyAlgebraic Geometry57T15, 14M15text