Solution
= Solution
A measure is a map $\mu:\mathcal A\to[0,\infty]$ with $\mu(\varnothing)=0$ and countable additivity on disjoint families.
= Solution
A measure is a map $\mu:\mathcal A\to[0,\infty]$ with $\mu(\varnothing)=0$ and countable additivity on disjoint families.