Let $ \mathring{H}^s$ be the closure of $ \mathcal{D}(\Omega)$ under the norm $ \mathring{H}^s$ . It is well-known that $ $ [L^2(\Omega), \mathring{H^{2}}(\Omega)]_{\theta}=\mathring{H^{2s}}(\Omega) \quad \forall \theta\in[0,1]\, \text{and } \theta\neq \frac{3}{4} $ $ when $ \Omega$ is bounded and smooth. What is the interpolation result when $ \Omega$ is Lipschitz continuous. What is the optimal regularityRead more