An intrinsic metric approach to uniqueness of the positive Cauchy–Neumann problem for parabolic equations

We study uniqueness of nonnegative solutions of the Cauchy–Neumann problem for parabolic equations in unbounded domains, and give a sufficient condition for the uniqueness of nonnegative solutions to hold. We also give a parabolic Harnack inequality with Neumann boundary conditions.  2002 Elsevier Science (USA). All rights reserved.