Timeline for A remark by Gromov on 4-manifolds
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 5, 2012 at 22:43 | comment | added | Bruno Martelli | aha, he says "possibly with fixed points!", I presumed $\Gamma$ was acting freely, a stupid mistake. Thanks | |
| Aug 5, 2012 at 22:35 | comment | added | Anton Petrunin | @Bruno, check "On universal groups and three-manifolds" by Hilden--Lozano--Montesinos--Whitten | |
| Aug 5, 2012 at 22:17 | comment | added | Bruno Martelli | I don't understand that paragraph. He says that every 3-manifold is a quotient $S/\Gamma$ of a symmetric space by a discrete group of isometries $\Gamma$ quoting Thurston, but this fact is not true for all 3-manifolds (you need to remove essential spheres and tori), and one should quote Perelman instead of Thurston anyway. Then he says that in dimension $n\geqslant 4$ it is not known whether every manifold is homeomorphic to such a quotient $S/\Gamma$, but that looks not reasonable to me. What am I missing? | |
| Aug 5, 2012 at 22:03 | answer | added | Ian Agol | timeline score: 10 | |
| Aug 5, 2012 at 21:29 | history | asked | Thomas Riepe | CC BY-SA 3.0 |