Timeline for Scheme defined over $\mathbb{Z}$
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 13, 2021 at 10:31 | comment | added | YCor | There's a bad ambiguity between "defined over $\mathbf{Z}$" and "definable over $\mathbf{Z}$", which is not fixed by this answer, since "there is" is highly ambiguous. If it means "there exists", it should be "definable over $\mathbf{Z}$", often said "defined", and if it means "there is a given/ endowed with a given", it really means "defined over $\mathbf{Z}$". | |
| Nov 29, 2012 at 6:09 | vote | accept | LMN | ||
| Nov 29, 2012 at 6:09 | |||||
| Nov 29, 2012 at 6:07 | comment | added | LMN | The fact that the requirement "finite type" doesn't distinguish between these is the reason for my question. Requiring fppf for the structure map does distinguish, and my question is if this is the definition in arithmetic geometry. | |
| Nov 29, 2012 at 5:56 | comment | added | LMN | Sasha, your definition doesn't distinguish between things defined over $\textrm{Spec } \mathbb{Z}$ and those over $\textrm{Spec } \mathbb{Z}[1/N]$. I've certainly seen uses of this phrase that distinguish between these two (as above). | |
| Nov 29, 2012 at 5:42 | history | answered | Sasha | CC BY-SA 3.0 |