“…In the context of the flow in porous media, the fractional Laplacian that is derived from Lévy process models large motions through highly conductive layers or fractures, for example, [4,5] and the references therein. Although we do not discuss numerical aspects, the references are increasing, and we refer to only [6][7][8][9][10][11][12] and the references therein. Here, we do not intend to make any comprehensive list of numerical papers.…”