Let $X$ be a noetherian integral separated scheme which is regular in codimension one. According to Hartshorne's Algebraic Geometry, Prop. II.6.6, The divisor class group $Cl(X)$ is isomorphic to $Cl(X \times \mathbb{A}^1)$. Is the statement true when $\mathbb{A}^1$ is replaced with $\mathbb{A}^n$?
2026-04-23 06:32:17.1776925937
Is the divisor class group $Cl(X \times \mathbb{A}^n)$ isomorphic to $Cl(X)$?
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Sure because
$Cl(X\times \mathbb{A}^n)=Cl((X\times \mathbb{A}^{n-1})\times \mathbb{A})\cong$
$\cong Cl(X\times \mathbb{A}^{n-1})\cong \dots \cong Cl(X)$