Electronic Journal of Differential Equations, Vol. 2001(2001), No. 08, pp. 1-8. Title: Nonsmoothing in a single conservation law with memory Author: G. Gripenberg (Helsinki Univ. of Technology, Finland) Abstract: It is shown that, provided the nonlinearity $\sigma$ is strictly convex, a discontinuity in the initial value $u_0(x)$ of the solution of the equation $$ {\partial \over \partial t} \Big( u(t,x) + \int_0^t k(t-s) (u(s,x)-u_0(x))\,ds \Big) + \sigma(u)_x(t,x) = 0, $$ where $t>0$ and $x\in \mathbb{R}$, is not immediately smoothed out even if the memory kernel $k$ is such that the solution of the problem where $\sigma$ is a linear function is continuous for $t>0$. Submitted September 11, 2000. Published January 11, 2001. Math Subject Classifications: 35L65, 35L67, 45K05. Key Words: conservation law; discontinuous solution; memory.