Let $\{u_n\}$ be a sequence of functions in $H^1_0(\Omega)$ such that $u_n$ converges weakly to $u\in H^1(\Omega)$.
Then, can I conclude that $u$ is in fact in $H^1_0$?
Let $\{u_n\}$ be a sequence of functions in $H^1_0(\Omega)$ such that $u_n$ converges weakly to $u\in H^1(\Omega)$.
Then, can I conclude that $u$ is in fact in $H^1_0$?
Yes, because $H_0^1(\Omega)$ is a convex set which is norm-closed. -- Svetoslav
Reference: Convex set weakly closed if and only if strongly closed as well