Abstract We consider the following nonlocal critical problem with mixed Dirichlet–Neumann boundary conditions: (- Δ) s u = λ u + | u | 2 s * - 2 u in Ω, u = 0 on Σ 𝒟, ∂ u ∂ ν = 0 on Σ 𝒩, see text \{aligned (-) ^{su&= u+|% u|^2ₒ^{*-2}u&&, \\ u&=0&& % ₃, \\ u&=0&&% on ₍, aligned. where (- Δ) s (-) ^{s}, s ∈ (1 2, 1) s (1{2, 1) }, is the spectral fractional Laplacian operator,
Colorado et al. (Thu,) studied this question.