Timeline for direct image functor
Current License: CC BY-SA 2.5
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 10, 2010 at 3:42 | vote | accept | john | ||
| Dec 9, 2010 at 17:19 | answer | added | Sándor Kovács | timeline score: 3 | |
| Dec 9, 2010 at 17:06 | answer | added | Torsten Ekedahl | timeline score: 3 | |
| Dec 9, 2010 at 16:33 | comment | added | J.C. Ottem | Take $f$ to be a constant map, then the sequence is not exact. | |
| Dec 9, 2010 at 16:20 | comment | added | Francesco Polizzi | @Martin: the counterexample is not too difficult. I wrote it as an answer, in order to be clearer... | |
| Dec 9, 2010 at 16:15 | answer | added | Francesco Polizzi | timeline score: 3 | |
| Dec 9, 2010 at 15:49 | comment | added | Martin Brandenburg | @Francesco: Higher direct images does not have to vanish in general, but john has added some asssumptions. But perhaps this just makes it harder to find counterexamples. | |
| Dec 9, 2010 at 15:35 | comment | added | Francesco Polizzi | No. You should learn about derived functors, in particular $R^if_*$. Hartshorne's book is a good place to start. | |
| Dec 9, 2010 at 15:28 | history | asked | john | CC BY-SA 2.5 |