Quote:
Originally Posted by DSC
please help me with this horrible problem anyone, thanks!
Determine the subgroup lattice for Zp^n, where p is prime and n is some positive integer.

I trust that you really mean Zp^n and not GF(p^n).
The integers coprime to p^n form a multiplicative group mod p^n.
The integers mod (say) p^n1 do not form a group mod p^n.
I don't understand what you mean by "subgroup lattice'