Before revision:  For the space discretization  we introduce and analyze a high-order discontinuous Galerkin method on polygonal and polyhedral meshes, which is then coupled with Newmark-\beta time integration schemes.
After revision:  For the space discretization , we introduce and analyze a high-order discontinuous Galerkin method on polygonal and polyhedral meshes, which is then coupled with Newmark-\beta time integration schemes.