A Hardy-Littlewood-Sobolev type inequality for variable exponents and   applications to quasilinear Choquard equations involving variable exponent
  In this work, we have proved a version of the Hardy-Littlewood-Sobolev inequality for variable exponents. After we use the variational method to establish the existence of solution for a class of Choquard equations involving the $p(x)$-Laplacian operator. 
Claudianor O. Alves and Leandro da S. Tavares
math.AP