The following is the characterization theorem for $H^{-1}(U):=(H_0^1)^*(U)$in Evans's Partial Differential Equations:
Here is my question:
If one defines $H^{-1}(U)$ as the dual of $H^1(U)$ instead, is the theorem above still true?
Here
- $U$ is an open subset of $\mathbb{R}^{n}$
- $H^{1}(U)$ is the Sobolev space of $L^{2}(U)$ functions with weak derivatives in $L^{2}(U)$
- $H_{0}^{1}(U)$ is the closure of the subspace $\mathcal{C}_{c}^{\infty}(U)$ of compactly supported smooth functions on $U$
- $H^{-1}(U)$ is the (continuous) dual of $H_{0}^{1}(U)$
