convergent double series

例句：

1. 1.The convergence of the two series is a key factor in determining their sum.
   两个系列的收敛是确定其和的关键因素。
2. 2.The convergence of the series is a fundamental concept in the study of probability theory.
   系列收敛是概率理论研究中的基本概念。
3. 3.The convergence of the series is a measure of how quickly the values are approaching a common value.
   系列收敛是衡量值是否接近共同值的速度的指标。