Numerical Approximation of $\rho_t + div(\rho V) = 0$ Noel J. Walkington Department of Mathematical Sciences Carnegie Mellon University Abstract: The equation representing the balance of mass is a first order, linear, homogeneous, hyperbolic equation. The theory for this elementary equation becomes subtle when the velocity $V$ has low regularity; for example, solutions of the Navier Stokes equations with variable density and viscosity only lie in $L^2[0,T;H_0^1(\Omega)]$. This talk will give an overview of the theory developed in 1989 by DiPerna and P. L. Lions for this equation. This theory will then be used to establish strong convergence of DG schemes to approximate solutions.