A Posteriori Error Estimation for Interior Penalty Finite Element Approximations of the Advection-Reaction Equation

In this note we consider residual-based a posteriori error estimation for finite element approximations of the transport equation. For the discretization we use piecewise affine continuous or discontinuous finite elements and symmetric stabilization of interior penalty type. The lowest order discontinuous Galerkin method using piecewise constant approximation is included as a special case. The key elements in the analysis are a saturation assumption and an approximation result for interpolation between discrete spaces.