fact: Record group_on (G : monoid) : Type := {group_inverse_map : Map G G; group_inverse_r_prf : inverse_r (sgroup_law_map G) (monoid_unit G) group_inverse_map; group_inverse_l_prf : inverse_l (sgroup_law_map G) (monoid_unit G) group_inverse_map}.
imports: Monoid_cat