sigma function In number theory, the function σ(n) which is the sum of the factors of a positive integer n. For a perfect number σ(n) = 2n. The sigma function is an arithmetic function.
sigma function
数学辞典收录了4151条数学词条，基本涵盖了常用数学知识及数学英语单词词组的翻译及用法，是数学学习的有利工具。