English
The ghost components of the Witt-vector Frobenius functor shift by one index: ghostComponent n (frobeniusFun x) = ghostComponent (n+1) x.
Русский
Гост-компоненты Witt-функторa Фробениуса образуют сдвиг на единицу: ghostComponent n (frobeniusFun x) = ghostComponent (n+1) x.
LaTeX
$$$$\text{ghostComponent}_n(\operatorname{frobeniusFun}(x)) = \text{ghostComponent}_{n+1}(x).$$$$
Lean4
@[ghost_simps]
theorem ghostComponent_frobeniusFun (n : ℕ) (x : 𝕎 R) : ghostComponent n (frobeniusFun x) = ghostComponent (n + 1) x :=
by simp only [ghostComponent_apply, frobeniusFun, coeff_mk, ← bind₁_frobeniusPoly_wittPolynomial, aeval_bind₁]