In this article, we study the nonexistence of solution with finite Morse index for the following nonlinear elliptic equation for fractional Laplacian : (−∆) s u + λu = |u| p−1 u in R n + with ∂u/∂ν + cu = 0 on ∂R n +. where n ≥ 2s, 0 < s < 1, λ ≥ 0, c ≥ 0 and p > 1. The main methods used are the integral estimates, the Pohozaev-type identity and the monotonicity formula.
PACS: Primary : 35J55, 35J65 ; Secondary : 35B65.