English
For Φ ∈ MvPolynomial idx ℤ, the constant coefficient of WittStructureInt p Φ 0 equals the constant coefficient of Φ.
Русский
Для Φ ∈ MvPolynomial idx ℤ константный коэффициент WittStructureInt p Φ 0 равен константному коэффициенту Φ.
LaTeX
$$$\\operatorname{constantCoeff}(\\mathrm{wittStructureInt}\\, p \\, Φ \\, 0) = \\operatorname{constantCoeff} Φ$$$
Lean4
@[simp]
theorem constantCoeff_wittStructureInt_zero (Φ : MvPolynomial idx ℤ) :
constantCoeff (wittStructureInt p Φ 0) = constantCoeff Φ :=
by
have inj : Function.Injective (Int.castRingHom ℚ) := by intro m n; exact Int.cast_inj.mp
apply inj
rw [← constantCoeff_map, map_wittStructureInt, constantCoeff_wittStructureRat_zero, constantCoeff_map]