Phenomenological applications of the 1/N expansion

The main aspects of the 1/N approach to non-leptonic weak interactions developed in collaboration with Bardeen and Gerard are reviewed in detail. The results for the hadronic matrix elements relevant for K→ππ decays, K0-anti K0 mixing and CP violation in the K-system are presented. The implications of these results for the ΔI=1/2 rule in K→ππ decays and the CP violating parameters ε and ε' are discussed in detail. It is pointed out that the mass of the top quark (mt) should not be too large for the standard model to be able to fit the recent NA31 data for ε'/ε. An upper bound for mt is found as a function of various non-perturbative parameters. Typically mt<90 GeV is required. Implications of the B0-anti B0 mixing for ε'/ε and the value of mt are discussed. (orig.)