“…However, the application of this two methods needs extra conditions to be imposed on the solutions. Moreover, they do not work for nonlinear nonlocal operators, such as the fractional p-Laplacian(see [13] for details). Thanks to the works of Chen and Li et al in [9,10,11], direct methods of moving planes are introduced for the fractional Laplacian and fractional p-Laplacian without going through extensions or integral equations, which have been applied to obtain symmetry, monotonicity, and non-existence of solutions for various semi-linear equations involving these nonlocal operators.…”