arXiv2020
We prove the existence of ground state solution to the following problem. \begin{align*} (-Δ)^{s}u+u&=λ|u|^{-γ-1}u+P(x)|u|^{p-1}u,~\text{in}~\mathbb{R}^N\setminusΩ\\ N_su(x)&=0,~\text{in}~Ω\end{align*} where $N\geq2$, $λ>0$, $0<s,γ<1$, $p\in(1,2_s^*-1)$ with $2_s^*=\frac{2N}{N-2s}$. % $0<s^-=\underset{(x,y)\inΩ\timesΩ}{\inf}\{s(x,y)\}\leq s(x,y)\leq s^+=\underset{(x,y)\inΩ\timesΩ}{\sup}\{s(x,y)\}<1$, $0<γ^-=\underset{x\inΩ}{\inf}\{γ(x)\}\leq γ(x)\leq γ^+=\underset{x\inΩ}{\sup}\{γ(x)\}<1$, $1-γ^-<1<p^-=\underset{x\inΩ}{\inf}\{p(x)\}\leq p(x)\leq p^+=\underset{x\inΩ}{\sup}\{p(x)\}<2_{s^-}^*=\underset{x\inΩ}{\inf}\{2_s^*(x)\}$ with $2_s^*(x)=\frac{2N}{N-2\tilde{s}(s)}$ where $\tilde{s}(x)=s(x,x)$. Moreover, $Ω\subset\mathbb{R}^N$ is a smooth bounded domain, $(-Δ)^s$ denotes the $s$-fractional Laplacian and finally $N_s$ denotes the nonlocal operator that describes the Neumann boundary condition which is given as follows. \begin{align*} N_{s}u(x)&=C_{N,s}\int_{\mathbb{R}^N\setminusΩ}\frac{u(x)-u(y)}{|x-y|^{N+2s}}dy,~x\inΩ. \end{align*} We further establish the existence of infinitely many bounded solutions to the problem.