Constraining quark-hadron duality at large N-c - art. no. 116010

Quark-meson duality for two-point functions of vector and axial-vector QCD currents is investigated in the large-N-c approximation. We find that the j oint constraints of duality and chiral symmetry suggest degeneracy of excit ed vector and axial-vector mesons in the large-N-c limit. We compare model- independent constraints with expectations based on the Veneziano-Lovelace-S hapiro string model. Several models of duality are constructed, and phenome nological implications are discussed.