Symmetry and monotonicity of singular solutions for the Hartree equation

Abstract: In this paper we are concerned with positive singular solutions of the following nonlocal Hartree equation $$-\Delta u!=\Big( \int_{\mathbb{R}^N\setminus \Gamma}\frac{F(u(y))}{|x-y|^\mu}dy \Big)f (u(x)), \quad x\in \mathbb{R}^N\setminus\Gamma,$$ where $F$ is the primitive of $f$ and $\Gamma$ is the singular set. Under suitable assumptions, we prove that $u$ is symmetric and monotone with respect to the singular set by using moving plane methods. Furthermore, we complement this study by showing the existence, for a model problem, of a singular solution with the desired properties.