2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28463We propose a theoretical framework to describe the ladder systems. The N-chain Hubbard model has been studied within the Composite Operator Method. In this scheme of calculations the single-particle Green's function for any number of coupled chains is obtained by solving self-consistently a system of integral equations.6 pages, 1 embedded Postscript figure, LaTeX, to be published in Physica BStrongly Correlated Electronstext