On uniqueness and existence of entropy solutions of weakly coupled systems of nonlinear degenerate parabolic equations

Abstract

We prove existence and uniqueness of entropy solutions for the Cauchy problem of weakly coupled systems of nonlinear degenerate parabolic equations. We prove existence of an entropy solution by demonstrating that the Engquist-Osher finite difference scheme is convergent and that any limit function satisfies the entropy condition. The convergence proof is based on deriving a series of a priori estimates and using a general Lp compactness criterion. The uniqueness proof is an adaptation of Kružkov's "doubling of variables" proof. We also present a numerical example motivated by biodegradation in porous media.