Non-leptonic heavy-hadron decays and local duality

We discuss local duality for weak non-leptonic B and Λ_b decays in the m_b -> ∞ limit under the hypothesis of factorization and in the Shifman-Voloshin limit. We show that, under these hypotheses, local duality holds for the first two terms in the 1/m_b expansion and at the order α_s in the perturbative expansion. The possible relevance of these results for the operator product expansion evaluation of the b-hadron lifetimes is discussed.