函数是中学数学中的重要概念，同时又是近代数学的重要基础．由于它的意义比较抽象，所以就我国目前中学数学教材来看，所采用的函数定义，基本上还是属于在函数概念的发展史上，第三次扩张的“对应关系”的函数概念．而在美国的数学教材中对函数概念的处理则另辟蹊径，采... Function is an important concept in middle school mathematics, and it is also an important foundation of modern mathematics. Because its significance is relatively abstract, the definition of the function adopted by our country’s current middle school mathematics textbooks is basically a functional concept of the “correspondence relationship” in the history of function concept development and the third expansion. In the mathematics textbooks of the United States, the concept of function is treated differently.