[GAP Forum] Multiplicative Group modulo n

[Johannes Wachs]

Is there a way to call up the multiplicative group of order n?

In particular I have written a program to output some set of positive
integers. I want to test if they are a subgroup of the multiplicative group
mod n. It would be great if I could use Subgroup(G, L);

Alternatively, I think I could solve my problem by checking to see if my set
is closed under multiplication mod n. Is there a way to implement IsGroup
for some set mod n with multiplication?

Johannes Wachs