2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/151773We have studied the t-t'-U model by means of the composite operator method. The effect of the bare diagonal hopping term t' that appears to be material dependent for high-Tc cuprate superconductors is analyzed in detail. In particular, some local quantities are computed and a comprehensive comparison with the data by numerical simulations on finite size lattices is presented. The result show a good agreement with those obtained by Monte Carlo methods.3 pages, 3 figures in one Postscript file, RevTeX, to be published in Physica BStrongly Correlated ElectronsSuperconductivitytext