The Stacks project

Lemma 37.74.5. Let $f : X \to Y$ be a locally quasi-finite morphism with $X$ quasi-compact. Let $w : X \to \mathbf{Z}$ be a weighting of $f$. Then $\int _ f w$ attains its maximum.

Proof. It follows from Lemma 37.74.1 and Properties, Lemma 28.2.7 that $w$ only takes a finite number of values on $X$. It follows from Morphisms, Lemma 29.56.9 that $X \to Y$ has bounded geometric fibres. This shows that $\int _ f w$ is bounded. $\square$

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Your email address will not be published.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 0F3K. Beware of the difference between the letter 'O' and the digit '0'.