2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57150The generic renormalization group map associated to a weakly coupled system of fermions at temperature zero is treated by supplementing the methods of Part 1. The interplay between position and momentum space is captured by `sectors'. It is shown that the difference between the complete four legged vertex and its `ladder' part is irrelevant for the sequence of renormalization group maps.82 pages, 6 figuresMathematical Physics82B28 (Primary) 81T08 (Secondary)text