Dear GAP-Forum,

Avital Oliver asked the following question:

I accidently found a function SubdirectProducts which isn't documented. Can
I count on this function to work and return all the subdirect products of
two groups?

The function SubdirectProducts( S, T ) computes all subdirect products
of S and T up to conjugacy in the direct product Parent(S) x Parent(T).
The subdirect products are returned as subgroups of the direct product
Parent(S) x Parent(T).

Hence, if you set up your groups such that Parent(S) = S and Parent(T) = T,
then you will get all subdirect products up to conjugacy in S x T.

If you have groups S and G and you want G to be the parent of S, then you
can achieve this by 'S := Subgroup( G, GeneratorsOfGroup(S) );' (Provided
that S is indeed a subgroup of G of course.)

Best wishes,
          Bettina

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