Intermediate asymptotics of the porous medium equation with sign changes
Mark Bowen, Josephus Hulshof, John R. King · Advances in Differential Equations · 2001
We study the porous medium equation with sign changes and examine the way sign changes disappear. We give a formal classification of self-similar and non-self-similar scenarios for their disappearance, for $N>1,$ restricting attention to the radial case. The results we present on the classification of similarity solutions are rigorous except where indicated otherwise.