Bielliptic quotient modular curves of $X_0(N)$

Francesc Bars, Mohamed Kamel, Andreas Schweizer

Let $N\ge 1$ be a non-square free integer and let $W_N$ be a non-trivial subgroup of the group of the Atkin-Lehner involutions of $X_0(N)$ such that the modular curve $X_0(N)/W_N$…