Example 38.37.10. Let $A$ be a ring. Let $f \in A$ be an element. Let $J \subset A$ be a finitely generated ideal annihilated by a power of $f$. Then

$\xymatrix{ E = \mathop{\mathrm{Spec}}(A/fA + J) \ar[r] \ar[d] & \mathop{\mathrm{Spec}}(A/J) = X' \ar[d] \\ Z = \mathop{\mathrm{Spec}}(A/fA) \ar[r] & \mathop{\mathrm{Spec}}(A) = X }$

is an almost blowup square.

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