Timeline for Reference for Schur multiplier identity
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 6, 2019 at 12:02 | vote | accept | André Macedo | ||
| May 3, 2019 at 18:41 | answer | added | Derek Holt | timeline score: 6 | |
| May 3, 2019 at 18:14 | comment | added | Andrei Smolensky | @AndréMacedo Ah, indeed, this works only if $G$ is perfect (in which case the resulting formula also simplifies). | |
| May 3, 2019 at 18:09 | comment | added | André Macedo | @AndreiSmolensky, many thanks, but why is $H_2(\overline{G},\mathbb{Z})=0$? For $G=V_4$ we can have $\overline{G} \cong D_4$, which does not have trivial Schur multiplier... | |
| May 3, 2019 at 17:58 | comment | added | Andrei Smolensky | $K\leqslant \bar{H}\trianglelefteq \bar{G}$ and $\bar{G}/\bar{H}\cong G/H$. Now since $H_2(\bar{G})=0$, the usual proof using Stallings exact sequence carries to this setting, see the bottom of groupprops.subwiki.org/wiki/… | |
| May 3, 2019 at 16:21 | comment | added | Geoff Robinson | That is an elegant formula which I do not recognise in that form. I'll think before I write more. | |
| May 3, 2019 at 16:10 | review | First posts | |||
| May 3, 2019 at 16:15 | |||||
| May 3, 2019 at 16:06 | history | asked | André Macedo | CC BY-SA 4.0 |