Timeline for Fibrations and Euler characteristics with bad fundamental group
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
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| Mar 11, 2023 at 19:06 | comment | added | Maxime Ramzi | @GregoryArone : that sounds like a complete answer :) | |
| Mar 9, 2023 at 4:35 | comment | added | Gregory Arone | If $G$ is a finite group, $F$ is a finite complex with an action of $G$, and $E=F \times_G EG$. Then you have a fibration sequence $F\to E \to BG$. All three terms have finite rational cohomology, and $\chi(BG)=1$. But in general $\chi(E)\ne \chi(F)\chi(BG)$. The most obvious example is when $F$ is a finite set with a non-trivial action. It is also easy to find examples with connected $F$. | |
| Mar 8, 2023 at 15:36 | history | edited | Neil Strickland | CC BY-SA 4.0 |
edited title
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| Mar 8, 2023 at 14:41 | history | asked | Neil Strickland | CC BY-SA 4.0 |