设f,g为两个数论函数.
定义卷积运算(f×g)(n)=∑d|n[f(d)∗g(n/d)]
根据定义. (ι×f)(n)=∑d|nι(d)∗f(nd)=f(n) 所以可知. l(n) = { 1,n = 1 0, n = 0 }
根据定义.
(ι×f)(n)=∑d|nι(d)∗f(nd)=f(n)
所以可知.
l(n) = {
1,n = 1
0, n = 0
}