If $\norm{f_k}_p\le M$ for all $k$ and $f_k\to f$ almost everywhere, then $\norm{f}_p\le M$.Suggest a slogan
Let \((X,\mcm,\mu)\) be a measure space, \(1\leq p\leq\infty\), \(M\geq0\), and let \(f_k\colon X\to\CC\) be measurable with \(\norm{f_k}_p\leq M\) for all \(k\geq1\). If \(f_k\to f\) \(\mu\)-almost everywhere for a measurable \(f\colon X\to\CC\), then \(f\in L^p(\mu)\) and \(\norm{f}_p\leq M\).