I have the following situation : let $1< p < q < \infty$ . Consider in $\mathbb R^n$ the Lebesgue measure. Let $\{\varphi_n\}$ a sequence of functions in $C^{\infty} (D)$ ( $D$ a open subset of $\mathbb R^n$ not necessarialy bounded ) . Suppose $\int_{D} |\varphi_n |^q\rightarrow 0$.
I showed that (using Holder inequality) $\int_{G} |\varphi_n |^p\rightarrow 0$ where $G$ is a arbitrary subset of $D$ with the closure of G compact in R^n. Someone can give me a suggestion how to prove that
$$\int_{D} |\varphi_n |^p\rightarrow 0?$$
Thank you