isomorphism

Hi,

Can someone please tell me a method for describing Aut(Cn) as a product of cyclic groups

e.g describe Aut(C30) as a product of cyclic groups.

Thanks.

Quote:

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Originally Posted by jedoob

Hi,

Can someone please tell me a method for describing Aut(Cn) as a product of cyclic groups

e.g describe Aut(C30) as a product of cyclic groups.

Thanks.

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I never studied the automorphism group.
However, it seems to me that...

Aut(Z_n)
Has phi(n) elements and it is cyclic.
Hence,
Aut(Z_n) is isomorphic to Z_{phi(n)}.

I am assuming C_n means a cyclic group, right?