i1 : R = QQ[a..e];
i2 : C = cycle R;
i3 : UnmixedTree = graph {a*b, b*c, c*d};
i4 : MixedTree = graph {a*b, a*c, a*d};
i5 : isCM C o5 = true
i6 : isCM UnmixedTree o6 = true
i7 : isCM MixedTree o7 = false