Timeline for Projective scheme over the integers
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 27, 2022 at 19:07 | comment | added | Will Sawin | Yes, flatness is needed, or else you can take the union of $\mathbb P^1_{\mathbb F_p}$ and $\operatorname{Spec} \mathbb Z$, glued at an $\mathbb F_p$-point of $\mathbb P^1_{\mathbb F_p}$, whose mod $p$ fiber is $\mathbb P^1$, normal, and whose mod $q$ fiber is a point for any other point $q$, but is not normal. | |
| Sep 27, 2022 at 17:59 | comment | added | Armando j18eos | What is the ring where the prime ideal $p$ "lives"? | |
| Sep 27, 2022 at 17:53 | comment | added | fool rabbit | @Will Sawin I means for every p. Maybe I need add a condition such that $X$ is flat over $\mathbb{Z}$ | |
| Sep 27, 2022 at 17:05 | comment | added | Will Sawin | Do you mean "if for every $p$, $X_p$ is normal" or "If for at least one $p$, $X_p$ is normal"? | |
| Sep 27, 2022 at 16:58 | history | asked | fool rabbit | CC BY-SA 4.0 |