Situation 37.29.1. Here $f : X \to Y$ be a morphism of schemes, and $s : Y \to X$ is a section of $f$. For every $y \in Y$ we denote $X^0_ y$ the connected component of $X_ y$ containing $s(y)$. Finally, we set $X^0 = \bigcup _{y \in Y} X^0_ y$.

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