Timeline for Schur cover of alternating groups
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 5 at 8:26 | comment | added | YCor | One could ask, e.g., about the smallest permutation representation of this central extension of the symmetric (or alternating) group. | |
| Jun 5 at 8:25 | history | edited | YCor |
edited tags
|
|
| Jun 4 at 9:43 | answer | added | Achim Krause | timeline score: 6 | |
| Jun 4 at 7:58 | comment | added | Achim Krause | Don't you answer question (c) yourself? $[3,4][1,2]\neq - [3,4][1,2]$, as they differ by $-1$, the nontrivial element in the kernel of the map down to $S_n$. | |
| Jun 4 at 4:07 | comment | added | Ian Agol | The standard permutation map of $S_n$ gives a homomorphism to $O(n)$ when thought of as matrices, and $A_n = S_n \cap SO(n)$. $SO(n)$ has a double cover $Spin(n)$, and the double cover of $A_n$ is the pullback to this double cover I believe. $Pin(n)$ has a description in terms of Clifford algebras, as generated by preimage of reflections, so maybe one can get a “concrete” description out of that. | |
| Jun 4 at 3:02 | history | asked | stupid_question_bot | CC BY-SA 4.0 |