We study discretizations by powers of discrete Laplacians of fully nonlinear equations. Our problems are parabolic and of order σ є (0,2) since they involve fractional Laplace operators (-Δ)σ/2. They arise e.g. in control and game theory as dynamic programming equations, and solutions are non-smooth in general and should be interpreted as viscosity solutions. Our approximations are realized as finite-difference quadrature approximations which are 2nd order accurate for all values of σ. The accuracy of previous approximations depend on σ and are worse when σ is close to 2. We show that the schemes are monotone, consistent, L∞-stable, and convergent using a priori estimates, viscosity solutions theory, and the method of half-relaxed limits. We present several numerical examples.
2020 Mathematics Subject Classification. 49L25, 35J60, 34K37, 35R11, 35J70, 45K05, 49L25, 49M25, 93E20, 65N06, 65R20, 65N12.