Quark-hadron duality
= Quark-hadron duality
<Quark-hadron duality> is the correspondence, in suitable inclusive or averaged observables, between a quark-level description and a sum over hadronic states. <Asymptotic freedom> supports perturbative short-distance production, but sharp resonances and threshold regions can invalidate a pointwise partonic approximation. Inclusive predictions can have both radiative and nonperturbative corrections.