Let \((X,\mathcal M,\mu )\) be a measure space, and suppose that \(A_n\in \mathcal M\), \(n=1,\ldots \), with \[ \sum _{n=1}^{\infty }\mu (A_n)<\infty . \] Show that the set of \(x\) belonging to infinitely many \(A_n\) has measure zero.
Question
Math 6210 • Real Analysis
Fall 2016 • Question 4