# Commit 2022-09-08 10:32 9b6eef6e

View on Github →feat(number_theory/modular_forms/congruence_subgroups): Add definition of congruence subgroups. (#15159)
This contains the definition of a congruence subgroup of `SL(2,Z)`

and defines Gamma1, Gamma0 and full level subgroups. It also contains some basic results about them.