2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198709It is shown that the fundamental properties of gauge-independence, gauge-invariance, unitarity, and analyticity of the $S$-matrix lead to the unambiguous generalization of the pinch technique algorithm to two loops.4 pages, uses Revtex, two figures in a separate ps fileHigh Energy Physics - Phenomenologytext