The automorphism group of the non-split Cartan modular curve of level 11

Abstract

We derive equations for the modular curve $X_{ns}(11)$ associated to a non-split Cartan subgroup of ${\mathrm{GL}}_2({\mathbf{F}}_{11})$. This allows us to compute the automorphism group of the curve and show that it is isomorphic to Klein's four group.

Cited by in corpus (6)

• Automorphisms of Cartan modular curves of prime and composite level
• On the automorphisms of the non-split Cartan modular curves of prime level
• Double Covers of Cartan Modular Curves
• Quadratic Points on Non-Split Cartan Modular Curves
• Modular Curves with many Points over Finite Fields
• Functions and differentials on the non-split Cartan modular curve of level 11