Width of a cusp
= Width of a cusp
The width of a cusp represented by $\sigma\in SL_2(\mathbb Z)$ is the least positive $h$ such that $\sigma T^h\sigma^{-1}$ lies in the subgroup, up to its center. Its local parameter is $q_h=e^{2\pi i\tau/h}$.
= Width of a cusp
The width of a cusp represented by $\sigma\in SL_2(\mathbb Z)$ is the least positive $h$ such that $\sigma T^h\sigma^{-1}$ lies in the subgroup, up to its center. Its local parameter is $q_h=e^{2\pi i\tau/h}$.