Timeline for Isomorphism between subgroups by preserving index
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
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| Dec 3 at 9:55 | review | Close votes | |||
| 6 hours ago | |||||
| Jun 11, 2023 at 17:27 | comment | added | Christian Remling | I think what @YCor is asking is: if $G$ is an abstract group, what is the element of $G$ you call $-1$ ? | |
| Jun 11, 2023 at 3:12 | comment | added | verret | math.stackexchange.com/questions/4716245/… | |
| Jun 10, 2023 at 20:26 | answer | added | Christophe Leuridan | timeline score: 0 | |
| Jun 10, 2023 at 20:08 | review | Close votes | |||
| Jun 15, 2023 at 3:05 | |||||
| Jun 10, 2023 at 18:52 | comment | added | Anish Ray | @ChristopheLeuridan Kindly check the edited post. | |
| Jun 10, 2023 at 18:52 | comment | added | Anish Ray | @Ycor Kindly check the edited post. | |
| Jun 10, 2023 at 18:51 | history | edited | Anish Ray | CC BY-SA 4.0 |
added 314 characters in body
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| Jun 10, 2023 at 18:43 | comment | added | YCor | I cannot see how to make sense of "$A/\{\pm 1\}$" for a group $A$. | |
| Jun 10, 2023 at 18:39 | comment | added | Christophe Leuridan | You should clarify the assumptions. Assume explicitly that $C$ and $D$ have index $2$ in $A$ and $B$. Isomorphism is not sufficient: for example, the quotient of $\mathbb{U} = \{z \in \mathbb{C} : |z|=1\}$ by $\{-1,1\}$ is isomorphic to $\mathbb{U}$ itself. Do you assume that $\pi$ is an isomorphism? If you have only an homomorphism, for example the constant homomorphism which sends $A$ on $1_B$, it will not help. | |
| Jun 10, 2023 at 18:31 | history | asked | Anish Ray | CC BY-SA 4.0 |