Before revision:  Optimal convergence rates were proved for a conforming FEM discretization, albeit under a CFL stability condition where the global time-step, \Delta t, depends on the smallest elements in the mesh  .
After revision:  Optimal convergence rates were proved for a conforming FEM discretization, albeit under a CFL stability condition where the global time-step, \Delta t, depends on the smallest elements in the mesh \mbox{%DIFAUXCMD grote_sauter_1 .