summation of contraction

例句：

1. 1. The process of summation is a way to reduce the complexityof data.
   求和过程是一种减少数据复杂性的方法。
2. 2. The summation of contraction can be used to calculate the averagevalue of a set of numbers.
   求和集缩可以用来计算一组数字的平均值。
3. 3. Insummary, the summation of contraction is an important concept in data analysis.
   总之，求和集缩是数据分析中的一个重要概念。