Timeline for Cup products and the transfer map
Current License: CC BY-SA 2.5
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 11, 2011 at 17:39 | history | edited | Charles Rezk | CC BY-SA 2.5 |
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| Mar 11, 2011 at 17:39 | comment | added | Charles Rezk | Yep, I do mean to use $Z/p$ coefficients. You can lift this counterexample to integral cohomology: the $x\in H^2(C_p,Z/p)$ is the image of $\tilde{x}\in H^2(C_p,Z)$, and its still true that $\tau(\tilde{x})=0$ and $\tau(\tilde{x}^{p-1})\neq0$ in $H^*(\Sigma_p,Z)$. | |
| Mar 11, 2011 at 16:49 | comment | added | Neil Strickland | @Ralph: Charles secretly means to take cohomology everywhere with coefficients in $\Z/p$, and $p$ is secretly an odd prime. | |
| Mar 11, 2011 at 16:28 | comment | added | Ralph | But $H^2(\Sigma_3) = \mathbf{Z}/2$ (see Adem-Miglgram: "Cohomology of finite groups", Lemma IV.6.3)! | |
| Mar 11, 2011 at 16:07 | vote | accept | Troy A | ||
| Mar 11, 2011 at 16:05 | history | answered | Charles Rezk | CC BY-SA 2.5 |