Normal subgroups of the Alternating group $A_n$

Question

Is $A_{n-1}$ a normal subgroup of $A_n$? If so, why?

score 4 · Accepted Answer · answered Dec 02 '12 at 23:48

4

For $n\geq 5$, $A_n$ is simple, meaning it has no nontrivial normal subgroups.

answered Dec 02 '12 at 23:48

Julian Rosen

2

Should it not be 'no non-trivial proper normal subgroups'? – user50229 Dec 04 '12 at 20:41

1 Answers1