File:Z4latticeofsubgroups.png

This file was created using Graphviz with the following code:

digraph G{       rankdir = "BT"; Wholegroup[peripheries=2,label="{e,a,a^2,a^3}; for Z/4Z notation: {0,1,2,3}; whole group"]; Trivialsubgroup[peripheries=2,label="{e}; for Z/4Z notation: {0}; trivial"]; Middle[label="{e,a^2}; for Z/4Z notation: {0,2}; cyclic of order 2"]; Trivialsubgroup -> Middle -> Wholegroup; }