The role of the mean curvature in a mixed Hardy-Sobolev trace inequality

Abstract

Let $\Omega$ be a smooth bounded domain of $\mathbb{R}^{N+1}$ of boundary $\partial \Omega= \Gamma_1 \cup \Gamma_2$ and such that $\partial \Omega \cap \Gamma_2$ is a neighborhood of $0$, $h \in \mathcal{C}^0(\partial \Omega \cap \Gamma_2) $ and $s \in [0,1)$. We propose to study existence of positive solutions to the following Hardy-Sobolev trace problem with mixed boundaries conditions \begin{align} \begin{cases} \Delta u= 0& \qquad \textrm{ in } \Omega\\\ u=0 & \qquad \textrm{ on } \Gamma_1 \\\ \frac{\partial u}{\partial \nu}=h(x) u + \frac{u^{q(s)-1}}{d(x)^{s}} & \qquad \textrm{ on } \Gamma_2, \end{cases} \end{align} where $q(s):=\frac{2(N-s)}{N-1}$ is the critical Hardy-Sobolev trace exponent and $\nu$ is the outer unit normal of $\partial \Omega$. In particular, we prove existence of minimizers when $N \geq 3$ and the mean curvature is sufficiently below the potential $h$ at $0$.