∀ (p : ℕ) (R : Type u_1) [inst : Fact (Nat.Prime p)] (n : ℕ) (x : WittVector p (MvPolynomial R ℤ)),
  WittVector.mapFun (⇑(MvPolynomial.map (Int.castRingHom ℚ))) (n • x) =
    n • WittVector.mapFun (⇑(MvPolynomial.map (Int.castRingHom ℚ))) x