Bielliptic and Hyperelliptic modular curves X(N) and the group Aut(X(N))

Abstract

We determine all modular curves X(N) (with $N\ge 7$) which are hyperelliptic or bielliptic. We make available a proof that the automorphism group of X(N) coincides with the normalizer of $\Gamma (N)$ in ${\mathrm{PSL}}_2(\mathbb{R})$.

arXiv commentCorrected typos. Reorganized the whole paper. Main results unchanged

References in corpus (1)

• A New Automorphism Of X0(108)

Cited by in corpus (1)

• Bielliptic intermediate modular curves