Timeline for Non-realizability of $\mathbb{Q}$ as a cohomology group
Current License: CC BY-SA 3.0
6 events
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| Apr 13, 2017 at 12:19 | history | edited | CommunityBot |
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| Sep 23, 2015 at 23:48 | vote | accept | Aldo Guzmán Sáenz | ||
| Sep 23, 2015 at 17:47 | comment | added | Eric Wofsey | It follows easily from the universal coefficient theorem that this is equivalent to the existence of a group $A$ such that $\operatorname{Ext}(A,\mathbb{Z})\cong\mathbb{Q}$ (as $\mathbb{Q}$ is indecomposable, and $\operatorname{Hom}(A,\mathbb{Z})\cong\mathbb{Q}$ is impossible). | |
| Sep 23, 2015 at 17:31 | answer | added | Oscar Randal-Williams | timeline score: 15 | |
| Sep 23, 2015 at 16:03 | answer | added | Chris Gerig | timeline score: 2 | |
| Sep 23, 2015 at 15:31 | history | asked | Aldo Guzmán Sáenz | CC BY-SA 3.0 |