Timeline for open faithfully flat morphisms are fpqc
Current License: CC BY-SA 2.5
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 18, 2010 at 21:07 | vote | accept | Martin Brandenburg | ||
| Sep 18, 2010 at 13:14 | answer | added | Qing Liu | timeline score: 8 | |
| Sep 18, 2010 at 12:03 | comment | added | Martin Brandenburg | I don't understand. There are morphisms $f : X \to Y$, which are not quasi-compact, although $X$ is affine and $Y$ is quasi-compact. For example, take some affine $X$ which has an open subset $U$ which is not quasi-compact, and glue two copies of $X$ along $U$ to get $Y$. Then the, say first, inclusion $X \to Y$ is not quasi-compact. | |
| Sep 18, 2010 at 11:46 | comment | added | Matthieu Romagny | Well, if you take for $U$ any open affine neighbourhood of $x$ then $f(U)$ is open because $f$ is, and $U\to f(U)$ is quasi-compact because $U$ is... | |
| Sep 18, 2010 at 10:54 | history | asked | Martin Brandenburg | CC BY-SA 2.5 |