Normalizers of intermediate congruence subgroups of the Hecke subgroups
Bo-Hae Im, Daeyeol Jeon, Chang Heon Kim (2017)
Open Mathematics
Similarity:
For a square-free positive integer N, we study the normalizer of ΓΔ(N) in PSL2(ℝ) and investigate the group structure of its quotient by ΓΔ(N) under certain conditions.