Alternating group

[c299792458]

I have seen proofs that the alternating group A_n cannot have subgroups with index less than n. Ok, but what is the subgroup with index equal to n?

[morphism]

A_{n-1}?

[Deveno]

A_{n-1}?

this is true, but one should point out there there are usually several subgroups of An isomorphic to An-1 (each one fixing a different element of {1,2,...,n}).