A '''modular function''' is a [[meromorphic function]] that is [[Automorphism|automorphic]] with respect to a subgroup of the [[modular group]], i.e. it is invariant under a [[Group (mathematics)|group]] of linear transformations. | A '''modular function''' is a [[meromorphic function]] that is [[Automorphism|automorphic]] with respect to a subgroup of the [[modular group]], i.e. it is invariant under a [[Group (mathematics)|group]] of linear transformations. |