2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179301We construct a program to calculate Feynman amplitudes at finite temperature in the real time Keldysh formalism using the symbolic manipulation program {\it Mathematica}. As an example, the usefulness of this program is demonstrated by proving the finite temperature Ward identity for QED in a second order effective theory.Revtex 24 pages with 4 figures, A Mathematica program for Feynman diagrams added: MathFeynman.nbHigh Energy Physics - Phenomenologytext