Timeline for Reflexive sheaf
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 17, 2019 at 2:21 | comment | added | user39380 | Karl's answer modifies to an counterexample even if $X$ and $Y$ are isomorphic in codim $2$, for example, consider the blowup $k[x,y,z,w]/(xy-zw)$ along the plane $x=z=0$, then locally the map reads $k[x,y,z,w]/(xy-zw)\to k[x,z,w], x\mapsto x, y\mapsto zw, z\mapsto zx, w\mapsto w$, the pullback of the ideal $(y,z)$ has an nontrivial element $y\otimes x-z\otimes w$ annihilated by $yz$. | |
| Apr 16, 2013 at 2:29 | comment | added | Emerton | Dear John, Outside of codim'n two on $X$ or on $Y$? Regards, | |
| Apr 15, 2013 at 18:04 | answer | added | Karl Schwede | timeline score: 5 | |
| Apr 15, 2013 at 17:52 | history | asked | john | CC BY-SA 3.0 |