Lemma 29.37.6. Let $f : X \to S$ be a morphism of schemes. Then $f$ is quasi-affine if and only if $\mathcal{O}_ X$ is $f$-relatively ample.

[II Proposition 5.1.6, EGA]

**Proof.**
Follows from Properties, Lemma 28.27.1 and the definitions.
$\square$

## 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Your email address will not be published.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.

## Comments (2)

Comment #2708 by Matt Stevenson on

Comment #2745 by Takumi Murayama on

There are also: