On the non-vanishing of Poincaré series
On the non-vanishing of Poincaré series
R. A. Rankin [2] and J. Lehner [ 1 ] considered the non-vanishing of Poincaré series for the classical modular matrix group and for an arbitrary fuchsian group, respectively. In this paper we consider the non-vanishing of Poincaré series for the congruence group