ヘルダー平均
M 0 ( x 1 , ... , x n ) ≡ lim p → 0 M p ( x 1 , ... , x n ) = x 1 ... x n n {\displaystyle M_{0}(x_{1},\dots ,x_{n})\equiv \lim _{p\to 0}M_{p}(x_{1},\dots ,x_{n})={\sqrt[{n}]{x_{1}\dots x_{n}}}}