sufficient condition for mean convergence in $L^1$:prove or disprove Let $f_n \; \colon (0,1) \to \mathbb{R} $ a sequence of Lebesgue integrable functions which converges almost everywhere in $(0,1)$ to $0$. Prove or Disprove: if there exists $p \in (1,+ \infty)$ such that $(f_n)$ is bounded in $L^p(0,1)$,then $\lim_{ n \to \infty} \int_0^1|f_n(x)| \, dx =0$.

I think the property is true and Egorov's theorem will help here. Fix $\varepsilon >0$. Since $f_n \to 0$ a.e., there is a set $E \subset (0,1)$ such that $\lvert E\rvert < \varepsilon$ and $f_n \to 0$ uniformly on $(0,1)\setminus E$. Now fix $\delta > 0$ and $N$ large enough that $\lvert f_n \rvert < \delta$ on $(0,1)\setminus E$ whenever $n \ge N$. Then for $n \ge N$, \begin{align*} \int^1_0 \lvert f_n(x)\rvert dx &= \int_{(0,1)\setminus E} \lvert f_n(x)\rvert dx + \int_E \lvert f_n(x)\rvert dx \\ 
&\le \delta \int_{(0,1)\setminus E}dx + \lvert E \rvert^{1/q}\|f_n\|_{L^p(0,1)}\\
&\le \delta + \varepsilon^{1/q}M
\end{align*} where $M$ is the bound on $f_n$ in $L^p(0,1)$, and $q$ is the dual exponent to $p$. Since $\varepsilon$ and $\delta$ are arbitrary, this shows that $\int^1_0 \lvert f_n(x)\rvert dx \to 0.$
