2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52216This paper describes my talk given to the 27th Johns Hopkins Workshop: Symmetries and Mysteries of M Theory, Göteborg, Sweden, 24-26 August, 2003. After a brief introduction to the lightcone worldsheet formalism for summing the planar diagrams of field theory, I explain how the {\it uv} divergences of quantum field theory translate to the new language of string. It is shown through one loop that, at least for scalar cubic vertices, the counter-terms necessary for Poincaré invariance in space-time dimensions $D\leq 6$ are indeed local on the worldsheet. The extension to cover the case of gauge field vertices will be more complicated due to the extra divergences at $p^+=0$ in lightcone gauge.11 pages, 2 figures, talk to 27th Johns Hopkins WorkshopHigh Energy Physics - Theorytext