2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149817The purpose of this note is to show how the Kawamata-Viehweg vanishing theorem for fractional divisors leads to a quick new proof of Bogomolov's instability theorem for rank two vector bundles on an algebraic surface.7 pages, LaTexAlgebraic Geometrytext