Groundstates for nonlinear fractional Choquard equations with general nonlinearities

We study the following nonlinear Choquard equation driven by a fractional Laplacian: $$(-\mathrm{\Delta }{)}^{s}u+u=(\mathrm{\mid }x{\mathrm{\mid }}^{-\mu }\ast F(u))f(u)\mathrm{\mid }4.14mmin\mathrm{\mid }1.14mm{\mathbb{R}}^N,$$ with $N\ge 3$, $s\in (0,1)$ and $\mu \in (0,N)$. By Supposing that the nonlinearities satisfy the general Berestycki-Lions type conditions \cite{BL}, we are able to prove the existence of groundstates for this equation by variational methods.