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Dear Gap Forum,

W. Liebert wrote:

> In response to your answer to Pat Callahan's question: Do I also use the

> function 'AutomorphismPGroup' if I want to compute the automorphism group

> of a finite abelian p-group?

At the moment this seems to be the most efficient way to compute the

automorphism group of a finite abelian group with GAP.

However, with a little bit of effort, one can more or less read off the

automorphism group of a finite abelian group from its cyclic decomposition.

(See, for instance, Kenjiro Shoda, "Uber die Automorphismen einer endlichen

abelschen Gruppe, Math. Ann. 100 (1928), 674 - 686.)

Alexander Hulpke has implemented this method, but it is not yet part of

the standard distribution of GAP. If there is demand for it, we would be

happy to supply this function.

Best wishes,

Bettina Eick

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