Waiting-Time Behavior in a Nonlinear Diffusion Equation

We study the nonlinear diffusion equation u_t*=(u^nu_x)_x, which occurs in the study of a number of problems. Using singular‐perturbation techniques, we construct approximate solutions of this equation in the limit of small n. These approximate solutions reveal simply the consequences of this variable diffusion coefficient, such as the finite propagation speed of interfaces and waiting‐time behavior (when interfaces wait a finite time before beginning to move), and allow us to extend previous results for this equation