The Stacks project

Theorem 41.6.2. Let $Y$ be a connected scheme. Let $f : X \to Y$ be unramified and separated. Every section of $f$ is an isomorphism onto a connected component. There exists a bijective correspondence

\[ \text{sections of }f \leftrightarrow \left\{ \begin{matrix} \text{connected components }X'\text{ of }X\text{ such that} \\ \text{the induced map }X' \to Y\text{ is an isomorphism} \end{matrix} \right\} \]

In particular, given $x \in X$ there is at most one section passing through $x$.

Proof. Direct from Proposition 41.6.1 part (3). $\square$

Comments (0)

Post a comment

Your email address will not be published. Required fields are marked.

In your comment you can use Markdown and LaTeX style mathematics (enclose it like $\pi$). A preview option is available if you wish to see how it works out (just click on the eye in the toolbar).

Unfortunately JavaScript is disabled in your browser, so the comment preview function will not work.

All contributions are licensed under the GNU Free Documentation License.




In order to prevent bots from posting comments, we would like you to prove that you are human. You can do this by filling in the name of the current tag in the following input field. As a reminder, this is tag 024U. Beware of the difference between the letter 'O' and the digit '0'.



View Theorem 41.6.2 as pdf