∀ (R : Type u) (A : Type v) (B : Type w) [inst : CommSemiring R] [inst_1 : AddCommMonoid A] [inst_2 : AddCommMonoid B]
  [inst_3 : Module R A] [inst_4 : Module R B] [inst_5 : Coalgebra R A] [inst_6 : Coalgebra R B],
  CoalgebraStruct.counit ∘ₗ LinearMap.inr R A B = CoalgebraStruct.counit