Convergence of the Grünwald-Letnikov scheme for time-fractional diffusion

  • Authors:
  • R. Gorenflo;E. A. Abdel-Rehim

  • Affiliations:
  • Department of Mathematics and Computer Science, Free University of Berlin, Arnimallee 3, D-14195 Berlin, Germany;Department of Mathematics and Computer Science, Suez Canal University, Ismailia, Egypt

  • Venue:
  • Journal of Computational and Applied Mathematics
  • Year:
  • 2007

Quantified Score

Hi-index 7.29

Visualization

Abstract

Using bivariate generating functions, we prove convergence of the Grunwald-Letnikov difference scheme for the fractional diffusion equation (in one space dimension) with and without central linear drift in the Fourier-Laplace domain as the space and time steps tend to zero in a well-scaled way. This implies convergence in distribution (weak convergence) of the discrete solution towards the probability of sojourn of a diffusing particle. The difference schemes allow also interpretation as discrete random walks. For fractional diffusion with central linear drift we show that in the Fourier-Laplace domain the limiting ordinary differential equation coincides with that for the solution of the corresponding diffusion equation.