2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57151A self contained analysis demonstrates that the sum of all particle-hole ladder contributions for a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve at temperature zero is bounded. This is used in our construction of two dimensional Fermi liquids.131 pages, 26 figuresMathematical Physics82B28 (Primary) 81T08 (Secondary)text