Timeline for compact quotient
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 2, 2012 at 3:58 | comment | added | Nik Weaver | Oh, you're right. So let me think about whether my counterexample can be modified to be locally compact. | |
| Aug 2, 2012 at 2:22 | comment | added | Noah Stein | The quotient map $f: [0,1]\to S^1$ which glues $0$ to $1$ is not open: $f^{-1}\left(f\left([0,\delta)\right)\right)$ contains $1$ but does not contain $(1-\epsilon,1]$ for any $\epsilon$. | |
| Aug 1, 2012 at 23:23 | comment | added | Nik Weaver | Quotient maps are always open, aren't they? So I think you've shown there is no locally compact counterexample. | |
| Aug 1, 2012 at 23:00 | history | answered | Ian Agol | CC BY-SA 3.0 |