English
In a commutative semiring, a single variable X_s is a non-zero divisor in the multivariate polynomial ring.
Русский
В коммутативном полурусале переменная X_s не является делителем нуля в кольце многочленной.
LaTeX
$$$IsRegular(X_s) $$$
Lean4
@[simp]
theorem isRegular_X : IsRegular (X n : MvPolynomial σ R) :=
by
suffices IsLeftRegular (X n : MvPolynomial σ R) from ⟨this, this.right_of_commute <| Commute.all _⟩
intro P Q (hPQ : (X n) * P = (X n) * Q)
ext i
rw [← coeff_X_mul i n P, hPQ, coeff_X_mul i n Q]