A continuous space-time finite element method for the wave equation

The consider a finite element method for the nonhomogeneous second-order wave equation, which is formulated in terms of continuous approximation functions in both space and time, thereby giving a unified treatment of the spatial and temporal discretizations. Our analysis uses primarily energy arguments, which are quite common for spatial discretizations but not for time. We present a priori nodal (in time) superconvergence error estimates without any special time step restrictions. Our method is based on tensor product spaces for the full discretization.