R−{0,−13}\mathbb{R}-\left\{0,-\frac{1}{3}\right\}R−{0,−31}
R−{13}\mathbb{R}-\left\{\frac{1}{3}\right\}R−{31}
R−{0,−16}\mathbb{R}-\left\{0,-\frac{1}{6}\right\}R−{0,−61}
R−{0,16}{\mathbb{R}}-\left\{0, \frac{1}{6}\right\}R−{0,61}