English
If p is prime, then the constant coefficient of the Witt polynomial wittPolynomial p R n is zero for every n.
Русский
Если p — простое число, то константный коэффициент Witt-полины wittPolynomial p R n равен нулю для любого n.
LaTeX
$$$ \operatorname{constantCoeff}( wittPolynomial\ p\ R\ n ) = 0 $$$
Lean4
@[simp]
theorem constantCoeff_wittPolynomial [hp : Fact p.Prime] (n : ℕ) : constantCoeff (wittPolynomial p R n) = 0 :=
by
simp only [wittPolynomial, map_sum, constantCoeff_monomial]
rw [sum_eq_zero]
rintro i _
rw [if_neg]
rw [Finsupp.single_eq_zero]
exact ne_of_gt (pow_pos hp.1.pos _)