2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/78647Recently the second named author discovered a combinatorial identity in the context of vertex representations of quantum Kac-Moody algebras. We give a direct and elementary proof of this identity. Our method is to show a related identity of distributions.7 pagesQuantum AlgebraCombinatorics05E; 17Btext