##### 勒贝格积分基础运算
- 勒贝格积分基础运算
- 线性
- $\displaystyle \int_X (af + bg) \text{d}\mu = a \int_X f \text{d}\mu + b \int_X g \text{d}\mu$
- 单调性
- $\displaystyle \int_X f \text{d}\mu \leq \int_X g \text{d}\mu$
- 绝对值不等式
- $\displaystyle \left| \int_X f \text{d}\mu \right| \leq \int_X |f| \text{d}\mu$