2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47891In this talk we discuss the general method to calculate loop corrections to Delta S=1 density-density operators in the 1/N_c approach. As a result we present the long-distance evolution of the operators Q_6 and Q_8 to O(p^0/N_c) in the chiral and the 1/N_c expansions.12 pages, 5 eps figures. Talk presented at the XVI Autumn School and Workshop on Fermion Masses, Mixing and CP Violation, Lisboa, Portugal, 6-15 October 1997High Energy Physics - Phenomenologytext