Kleene's theorem on regular set

例句：

1. 1.Kleene's theorem is a fundamental concept in computer science.
   克莱恩定理是计算机科学中的一个基本概念。
2. 2. The theorem was proven using mathematical proofs and logical reasoning.
   这个定理是通过数学证明和逻辑推理被证明的。
3. 3. Kleene's theorem has been applied to various fields of study, including computer science and mathematics.
   克莱恩定理已经被应用到许多领域，包括计算机科学和数学。