GAP4没有与IdGroup对应的IdRing命令： 例如： for j in [1..2] do for i in [1..11] do R:=DirectSum(SmallRing(4,i),SmallRing(2,j));;Print("i=",i,"j=",j,","IdRing(R),"\n");od;od; 实际上22种8阶直积环（去掉重复的R8_27、R8_40后剩20种）应该输出如