2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179265We recompute the functions describing the collinear factorization of one-loop amplitudes using the unitarity-based method. We present the results in a form suitable for use as an ingredient in two-loop calculations. We also present a function summarizing the behavior at one loop in both the soft and collinear limits.two references added, minor changes in the textHigh Energy Physics - Phenomenologytext