Timeline for Irrationality of some threefolds
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
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| Dec 30, 2021 at 23:09 | vote | accept | Basics | ||
| Dec 30, 2021 at 12:37 | history | edited | Martin Sleziak | CC BY-SA 4.0 |
typo in the title
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| Dec 30, 2021 at 12:20 | answer | added | Jason Starr | timeline score: 3 | |
| Dec 29, 2021 at 11:49 | comment | added | Jason Starr | If the quotient of the K3 surface is irrational, then you are done (but I guess the construction -- whatever it is -- precludes this case). If the quotient is rational, then your threefold fibers over that rational surface with geometric fibers that are rational curves. Since the involution on the projective line also has fixed points, this projection to the rational surface has a section. For a threefold that is a conic bundle over a rational surface and admits a section, the threefold is rational (in fact the base change to the generic point of the surface is rational). | |
| Dec 29, 2021 at 7:25 | comment | added | Sasha | It does not look easy to understand the definition in the paper you cite, so it would be better if you provide more details here. | |
| Dec 29, 2021 at 5:55 | history | edited | Basics | CC BY-SA 4.0 |
added 6 characters in body
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| Dec 29, 2021 at 5:49 | history | asked | Basics | CC BY-SA 4.0 |