“…In the limit σ → 2 we recover the standard Porous Medium Equation ∂u ∂t + ∆(|u| m−1 u) = 0, for which the numerical solution has been studied by many authors, either in itself of as part of the study of the class degenerate parabolic equations, see e.g. [1,3,11,13,15,16,18,20,21,24] for the earlier literature.…”