Key points are not available for this paper at this time.
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
C. J. Mozzochi (Wed,) studied this question.