“…Some remarkable extensions have already been obtained on the upper half space by Dou and Zhu [31] and on compact Riemannian manifolds by Han and Zhu [42]. The reversed (weighted) Hardy-Littlewood-Sobolev inequalities were derived in [12,32,58,59]. For more results concerning the (weighted) Hardy-Littlewood-Sobolev inequality and Hardy-Sobolev equations, please refer to [2,3,8,11,18,19,20,22,23,24,25,26,28,47,50,53,56,62] and the references therein.…”