Prescribed Gauss curvature problem on singular surfaces

Abstract

We study the existence of at least one conformal metric of prescribed Gaussian curvature on a closed surface $\Sigma$ admitting conical singularities of orders ${\alpha }_i$'s at points $p_i$'s. In particular, we are concerned with the case where the prescribed Gaussian curvature is sign-changing. Such a geometrical problem reduces to solving a singular Liouville equation. By employing a min-max scheme jointly with a finite dimensional reduction method, we deduce new perturbative results providing existence when the quantity $\chi (\Sigma )+{\sum }_i{\alpha }_i$ approaches a positive even integer, where $\chi (\Sigma )$ is the Euler characteristic of the surface $\Sigma$.