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Exercise 111.34.2. Consider the morphism of schemes

\[ \pi : X = \mathop{\mathrm{Spec}}(\mathbf{C}[x, t]/(x^2 + t)) \longrightarrow S = \mathop{\mathrm{Spec}}(\mathbf{C}[t]). \]

Show there does not exist a nonempty open $U \subset S$ and a morphism $\sigma : U \to X$ such that $\pi \circ \sigma = \text{id}_ U$.

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View Exercise 111.34.2 as pdf