2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/185624The gauge dependence of the time-ordered products for Yang-Mills theories is analysed in perturbation theory by means of the causal method of Epstein and Glaser together with perturbative gauge invariance. This approach allows a simple inductive proof of the gauge independence of the physical S-matrix.19 pages, latex, 1 figureHigh Energy Physics - Theorytext