Suppose \((X,\mathcal M,\mu )\) is a measure space and \(f:X\to \mathbb R\) is a real-valued function on \(X\). Suppose further that \(E_r:=\{x\mid f(x)>r\}\) is measureable for each rational number \(r\). Either prove the following assertion or find a counter-example: \(f\) is measureable.
Question
Math 6210 • Real Analysis
Fall 2010 • Question 1