Let \((X,\mathfrak M,\mu )\) be a measure space, and let \(A_1\supset A_2\supset \cdots \supset A_n\supset \cdots \) be a sequence of sets in \(\mathfrak M\).
Is it always true that \(\mu (\bigcap _{n=1}^{\infty }A_n)=\lim _{n\to \infty }\mu (A_n)\)? If so, give a proof. Otherwise give a counterexample.