The Stacks project

Definition 5.12.1. Quasi-compactness.

  1. We say that a topological space $X$ is quasi-compact if every open covering of $X$ has a finite subcover.

  2. We say that a continuous map $f : X \to Y$ is quasi-compact if the inverse image $f^{-1}(V)$ of every quasi-compact open $V \subset Y$ is quasi-compact.

  3. We say a subset $Z \subset X$ is retrocompact if the inclusion map $Z \to X$ is quasi-compact.

Comments (0)

There are also:

  • 3 comment(s) on Section 5.12: Quasi-compact spaces and maps

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Your email address will not be published.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 005A. Beware of the difference between the letter 'O' and the digit '0'.



View Definition 5.12.1 as pdf