MC Approximation theory In mathematics,approximation theory is concerned with how functions can best be approximated with simpler functions,and with quantitatively characterizing the errors introduced thereby. 用来近似真实函数的简 单函数最好是正交的 (Svf)(r)=∑f(n)emr, n=-N ynh.cxh @ustc.edu.cn{ynh,cxh}@ustc.edu.cn Approximation theory In mathematics, approximation theory is concerned with how functions can best be approximated with simpler functions, and with quantitatively characterizing the errors introduced thereby. 用来近似真实函数的简 单函数最好是正交的