2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/71717Multiple harmonic sums appear in the perturbative computation of various quantities of interest in quantum field theory. In this article we introduce a class of Hopf algebras that describe the structure of such sums, and develop some of their properties that can be exploited in calculations.Talk for Loops & Legs in QFT, Zinnowitz, 2004Quantum AlgebraMathematical Physicstext