∀ (n : Type u_2) (R : Type u_3) (A : Type u_1) [inst : CommSemiring R] [inst_1 : Semiring A] [inst_2 : Algebra R A]
  [inst_3 : Fintype n] [inst_4 : DecidableEq n] (r : R),
  (↑↑(MatrixEquivTensor.toFunAlgHom n R A).toRingHom).toFun ((algebraMap R (TensorProduct R A (Matrix n n R))) r) =
    (algebraMap R (Matrix n n A)) r