2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60313Let C_*(K) denote the cellular chains on the Stasheff associahedra. We construct an explicit combinatorial diagonal Δ: C_*(K) --> C_*(K) \otimes C_*(K); consequently, we obtain an explicit diagonal on the A_\infty-operad. We apply the diagonal Δto define the tensor product of A_\infty-(co)algebras in maximal generality.Algebraic Topology57T30; 55U10; 55N20; 55N10text