Nonlocal fully nonlinear double obstacle problems

Abstract

We prove the existence, uniqueness, and $C^{1,\alpha }$ regularity of solutions to nonlocal fully nonlinear elliptic double obstacle problems. We also obtain boundary regularity for these problems. The obstacles are assumed to be Lipschitz semi-concave/semi-convex functions, and we do not require them to be $C^1$. Our approach is to adapt a penalization method to the setting of nonlocal equations and their viscosity solutions.