19 Apr
2016
19 Apr
'16
9:17 p.m.
If I understand the problem, it's to list all subgroups of the group of invertible elements of the ring Z/10. The invertible elements can be chosen as {-3, -1, 1, 3}. Since there is an element of order 4, this is isomorphic to the abelian group Z/4, so it has: * 1 subgroup of size 4, * 1 of size 2, * 1 of size 1: {-3, -1, 1, 3}, {-1, 1}, {1}. —Dan
On Apr 19, 2016, at 8:06 PM, Keith F. Lynch <kfl@KeithLynch.net> wrote:
List all multiplicative groups of integers mod ten. For instance {1,9} is one of them, and {1} is another.