The thin film equation with $2 \leq n<3$: finite speed of propagation in terms of the $L^1$-norm

Abstract

We consider the equation $u_t+(u^nu_{xxx})_x=0$ with $2\le n <3$ and establish an estimate for the finite speed of propagation of the support of compactly supported nonnegative solutions. The estimate depends only on the $L^1$-norm and is valid a posteriorifor strong solutions obtained through a Bernis-Friedman regularization.