pair A,B,C,D,E,F;
A:=(0,0); B:=(0,u); C:=(0,2u);
D:=(0,3u); E:=(0,4u); F:=(0,6u);

nodesize:=4bp;
nodespace:=6bp;

drawLoopPoint(A,B,"\varepsilon");
drawLoopPoint(A,C,"a");
drawLoopPoint(A,D,"b");
drawLoopPoint(A,E,"ab");
drawLoopPoint(A,F,"\omega");
draw (0,4.8u)--(0,5.8u) dashed withdots;
draw A withpen pencircle scaled 4bp;