The Group Structure of the Normalizer of Γ<sub>0</sub>(<i>N</i>) After Atkin–Lehner
The Group Structure of the Normalizer of Γ<sub>0</sub>(<i>N</i>) After Atkin–Lehner
We determine the group structure of the normalizer of Γ0(N) in SL 2(ℝ) modulo Γ0(N). These results correct the Atkin–Lehner statement (Atkin and Lehner, 1970 Atkin , A. O. L. , Lehner , J. ( 1970 ). Hecke operator on Γ0(N) . Math. Ann. 185 : 134 – 160 .[Crossref], …