∀ (p : ℕ) (R : Type u_1) [inst : CommRing R] [inst_1 : Fact (Nat.Prime p)] (x y : WittVector p (MvPolynomial R ℤ)),
  WittVector.mapFun (⇑(MvPolynomial.counit R)) (x - y) =
    WittVector.mapFun (⇑(MvPolynomial.counit R)) x - WittVector.mapFun (⇑(MvPolynomial.counit R)) y