Timeline for Failure of universal flatification
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 4, 2015 at 18:49 | vote | accept | Jonathan Wise | ||
| Dec 2, 2015 at 16:45 | answer | added | Jason Starr | timeline score: 4 | |
| Dec 2, 2015 at 14:43 | comment | added | Jason Starr | That example I suggested does not work: the domain has two irreducible components, and each of the two small resolutions "flattens" only one of the two irreducible components. | |
| Dec 2, 2015 at 12:08 | comment | added | Jason Starr | I do not know if this works, but how about the restriction over the determinantal locus in the target $\text{Zero}(det) \subset \text{Mat}_{2\times 2}$ of the matrix multiplication morphism $\text{Mat}_{2\times 2} \times \text{Mat}_{2\times 2} \to \text{Mat}_{2\times 2}$? | |
| Dec 2, 2015 at 3:06 | comment | added | Jonathan Wise | I'm most interested in the finitely presented case, but with non-proper support. | |
| Dec 1, 2015 at 15:01 | comment | added | Jason Starr | There is an appropriate Quot space that is proper over $S$ whenever the support of $M$ is proper over $S$ and $M$ is locally finitely presented. So counterexamples should have the support of $M$ not proper (or, in the non-Noetherian setting, $M$ not locally finitely presented). | |
| Dec 1, 2015 at 14:41 | history | asked | Jonathan Wise | CC BY-SA 3.0 |