Numerical conservation laws of time fractional diffusion PDEs

This paper introduces sufficient conditions to determine conservation laws of diffusion equations of arbitrary fractional order in time. Numerical methods that satisfy discrete counterparts of these conditions have conservation laws that approximate the continuous ones. On the basis of this result, we derive conservation laws for a mixed scheme that combines a finite difference method in space with a spectral integrator in time. A range of numerical experiments shows the convergence of the proposed method and its conservation properties.