recursive number theory

例句：

1. 1. The algorithm is designed to be recursive, allowing for easy modification and extension.
   这个算法被设计成递归的，便于修改和扩展。
2. 2. The process of learning is iterative, requiring repeated practice and review.
   学习的过程是迭代的，需要反复练习和复习。
3. 3. The cycle of life is cyclical, with each phase leading to the next.
   生命的循环是周期性的，每个阶段都通向下一个阶段。