Arithmetic subgroups act properly discontinuously #
instance
Subgroup.IsArithmetic.properlyDiscontinuous
{𝒢 : Subgroup (GL (Fin 2) ℝ)}
[𝒢.IsArithmetic]
:
Arithmetic subgroups of GL(2, ℝ) act properly discontinuously on ℍ.
Arithmetic subgroups of GL(2, ℝ) act properly discontinuously on ℍ.