2023-11-082023-11-082014-09https://www.sciencedirect.com/science/article/pii/S05503213140023751873-1562https://hdl.handle.net/10669/90306Renormalization of massless Feynman amplitudes in x-space is reexamined here, using almost exclusively real-variable methods. We compute a wealth of concrete examples by means of recursive extension of distributions. This allows us to show perturbative expansions for the four-point and two-point functions at several loop order. To deal with internal vertices, we expound and expand on convolution theory for log-homogeneous distributions. The approach has much in common with differential renormalization as given by Freedman, Johnson and Latorre; but differs in important details.engacceso abiertoRENORMALIZATIONMATHEMATICSPHYSICSartículo original10.1016/j.nuclphysb.2014.07.018