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Timeline for Circle bundles over $RP^2$

Current License: CC BY-SA 2.5

11 events
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Feb 20, 2022 at 19:55 answer added Ian Gershon Teixeira timeline score: 2
S Nov 3, 2015 at 7:25 history suggested Ali Taghavi
I add a tag
Nov 3, 2015 at 6:59 review Suggested edits
S Nov 3, 2015 at 7:25
Dec 2, 2009 at 23:51 comment added Charles Rezk To summarize Scott vs. Jason: for Scott, "circle bundle" means S^1 is the structure group, while for Jason, "circle bundle" means S^1 is the fiber.
Nov 30, 2009 at 16:34 answer added janmarqz timeline score: 4
Nov 23, 2009 at 12:56 vote accept Fernando Galaz-García
Nov 19, 2009 at 19:00 comment added Jason DeVito - on hiatus There are nonprincipal, nontrivial circle bundles. For example, the Klein bottle is an S^1 bundle over S^1 which is not principal and nontrivial. To see it's not principal, notice that principal circle bundles over S^1 are classified by homotopy classes of maps from S^1 into CP^\infty, but CP^\infty is 1-connected. Thus, the only principal S^1 bundle over S^1 is the trivial one, and hence the Klein bottle is NOT principal.
Nov 19, 2009 at 18:27 comment added S. Carnahan I apologize if I'm missing something: how do you get a circle bundle that's not principal? Do you mean "trivial" rather than "principal"?
Nov 19, 2009 at 18:17 answer added HJRW timeline score: 6
Nov 19, 2009 at 18:13 answer added Danny Calegari timeline score: 18
Nov 19, 2009 at 18:01 history asked Fernando Galaz-García CC BY-SA 2.5