绝对值(普通): ∥ x ∑ i = 1 n y i − y ∑ i = 1 n x i ∥ \| \frac{x}{\sum_{i=1}^{n}y_{i}} - \frac{y}{\sum_{i=1}^{n}x_{i}} \| ∥∑i=1nyix−∑i=1nxiy∥
绝对值(自动放缩): ∣ x ∑ i = 1 n y i − y ∑ i = 1 n x i ∣ \left| \frac{x}{\sum_{i=1}^{n}y_{i}} - \frac{y}{\sum_{i=1}^{n}x_{i}} \right| ∣∣∣∑i=1nyix−∑i=1nxiy∣∣∣
范数(普通): ∥ x ∑ i = 1 n y i − y ∑ i = 1 n x i ∥ \left\| \frac{x}{\sum_{i=1}^{n}y_{i}} - \frac{y}{\sum_{i=1}^{n}x_{i}} \right\| ∥∥∥∑i=1nyix−∑i=1nxiy∥∥∥
范数(自动放缩): ∥ x ∑ i = 1 n y i − y ∑ i = 1 n x i ∥ \left\| \frac{x}{\sum_{i=1}^{n}y_{i}} - \frac{y}{\sum_{i=1}^{n}x_{i}} \right\| ∥∥∥∑i=1nyix−∑i=1nxiy∥∥∥
小(圆)括号(普通): ( x ∑ i = 1 n y i ) ( \frac{x}{\sum_{i=1}^{n}y_{i}} ) (∑i=1nyix)
小(圆)括号(自动放缩): ( x ∑ i = 1 n y i ) \left( \frac{x}{\sum_{i=1}^{n}y_{i}} \right) (∑i=1nyix)
中(方)括号(普通): [ x ∑ i = 1 n y i ] [ \frac{x}{\sum_{i=1}^{n}y_{i}} ] [∑i=1nyix]
中(方)括号(自动放缩): [ x ∑ i = 1 n y i ] \left[ \frac{x}{\sum_{i=1}^{n}y_{i}} \right] [∑i=1nyix]
大(花)括号(普通): { x ∑ i = 1 n y i } \{ \frac{x}{\sum_{i=1}^{n}y_{i}} \} {
∑i=1nyix}
中(花)括号(自动放缩): { x ∑ i = 1 n y i } \left\{ \frac{x}{\sum_{i=1}^{n}y_{i}} \right\} {
∑i=1nyix}
尖括号(普通): < x ∑ i = 1 n y i > <\frac{x}{\sum_{i=1}^{n}y_{i}}> <∑i=1nyix>