Spherical growth of reciprocal classes in the Hecke Groups

Debattam Das, Krishnendu Gongopadhyay

Let $r\in \mathbb{Z}$, $r>2$, and let ${\Gamma }_{2r}\cong (\mathbb{Z}/2\mathbb{Z})\ast (\mathbb{Z}/2r\mathbb{Z})$ be the Hecke group. Let ${\mathcal{N}}_{\ell }$ denote the set of conjugacy…