∀ {R : Type u} [inst : CommSemiring R] {A : Type u_7} {B : Type u_8} [inst_1 : CommSemiring A] [inst_2 : CommSemiring B]
  [inst_3 : Algebra R A] [inst_4 : Algebra R B] [inst_5 : Algebra A B] [IsScalarTower R A B],
  (CommRing.Pic.mapAlgebra A B).comp (CommRing.Pic.mapAlgebra R A) = CommRing.Pic.mapAlgebra R B