  We use the Aleph data on vector and axial-vector spectral functions to test
simple duality properties of QCD in the large Nc limit, which emerge in the
approximation of a minimal hadronic ansatz of a spectrum of narrow states.
These duality properties relate the short- and long-distance behaviours of
specific correlation functions, which are order parameters of spontaneous
chiral symmetry breaking, in a way that we find well supported by the data.
