一个基础问题

来源: 于 2005-12-13 07:44:58 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

max{1,2,3}=3, max{}=? what number should be the answer if the set of positive numbers is empty? and the same problem
sum{1,2,3}=6, sum{}=? what number should be the answer if the set of positive numbers is empty? At some place sum{}=0. Is it the same for max{}?

Many thx.