Timeline for Finite flat pullback of the diagonal
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Mar 19, 2023 at 16:31 | comment | added | R. van Dobben de Bruyn | P.S. Another notation for $(f \times f)^{-1}(\Delta_Y)$ is $X \times_Y X$, so for instance that explains why $f$ is étale if and only if $\Delta_X \hookrightarrow (f\times f)^{-1}(\Delta_Y)$ is an open immersion [Tag 02GE]. | |
| Mar 19, 2023 at 14:24 | vote | accept | CommunityBot | ||
| Mar 19, 2023 at 14:23 | comment | added | R. van Dobben de Bruyn | In the separable case (e.g. characteristic $0$), the multiplicity will always be $1$; I added some details. | |
| Mar 19, 2023 at 14:21 | history | edited | R. van Dobben de Bruyn | CC BY-SA 4.0 |
Added more comments outside the étale Galois case.
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| Mar 19, 2023 at 14:08 | history | answered | R. van Dobben de Bruyn | CC BY-SA 4.0 |