fact: Structure Monoid : Type := {Mcarrier :> Setoid; Mop : BinOp Mcarrier; Munit : Mcarrier; Prf_monoid_ass : Monoid_ass Mop; Prf_monoid_idl : Monoid_idl Mop Munit; Prf_monoid_idr : Monoid_idr Mop Munit}.
imports: Map2