Timeline for On some loci of rings
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Sep 16, 2021 at 21:55 | comment | added | TNAn | Thank @KarlSchwede very much for your comment. I understand the second part now. | |
| Sep 15, 2021 at 14:49 | comment | added | Karl Schwede | I don't know an algorithm for 1, if you are finite type over a perfect field you can use the Jacobian, or see the recent work of Hochster-Jeffries. For 2, there are options. First, a ring is Gorenstein if and only if it is Cohen-Macaulay with locally free canonical module. The non-Cohen-Macaulay locus can be expressed as the vanishing of the annihilator of certain Ext groups. The locus where the canonical module $\omega_R$ is not locally free can be computed in various ways (from homological, to in the case of a reduced ring, via a map $\omega_R \cdot \omega_R^{-1} \to R$). | |
| Sep 15, 2021 at 0:55 | history | asked | TNAn | CC BY-SA 4.0 |