In Lars Hormander's An Introduction to Complex Analysis in Several Variables, page 77, he says that"every function in $L^2(\Omega, loc)$ belongs to $L^2(\Omega,\phi)$ for some continuous $\phi$ , where $L^2(\Omega,\phi)$ has the measure $e^{-\phi}d\lambda$. Why is that?
$\Omega$is open and $d\lambda$ is the Lesbegue measure