∀ {R : Type u} [inst : CommRing R] {p : ℕ} [inst_1 : Fact (Nat.Prime p)] [inst_2 : Fact ¬IsUnit ↑p]
  [inst_3 : IsAdicComplete (Ideal.span {↑p}) R],
  Function.Surjective ⇑(frobenius (ModP R p) p) → Function.Surjective ⇑(WittVector.fontaineTheta R p)