Timeline for Descending étaleness
Current License: CC BY-SA 3.0
3 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 16, 2013 at 20:23 | comment | added | Matthieu Romagny | Yes, at least if you assume moreover that $f$ is locally of finite presentation. Indeed, first $X\times_Y Y^n\to Y^n$ flat implies $X\to Y$ flat by EGA4, part 3, prop. 11.5.5. Second, being unramified is a property that depends only on the fibres, so $X\times_Y Y'\to Y'$ unramified always implies $X\to Y$ unramified for $Y'\to Y$ surjective. | |
| Dec 16, 2013 at 20:18 | answer | added | Vinteuil | timeline score: 5 | |
| Dec 16, 2013 at 19:11 | history | asked | alfs | CC BY-SA 3.0 |