R−{43}\mathbb{R}-\left\{\frac{4}{3}\right\}R−{34}
R−{23}\mathbb{R}-\left\{\frac{2}{3}\right\}R−{32}
R−{32}R-\left\{\frac{3}{2}\right\}R−{23}
R−{34}\mathbb R-\left\{\frac{3}{4}\right\}R−{43}