2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/119078We find a Lax pair equation corresponding to the Connes-Kreimer Birkhoff factorization of the character group of the Hopf algebra of Feynman diagrams. In particular, we obtain a flow for the character given by Feynman rules, and present a worked example.Mathematical Physicstext