2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56042We show that, as a consequence of a physical interpretation based on the Abelian projection and on the QCD string, four-dimensional QCD confines the electric flux if and only if the functional integral in the fiberwise-dual variables admits a hyper-Kahler reduction under the action of the gauge group.8 pages, latex, no figures, a misprint correctedHigh Energy Physics - Theorytext