Lagrange and average interpolation over 3D anisotropic elements
The author defines an average interpolant operator over 3-rectangles and tetrahedra, and proves optimal order error estimates in the \(H^1\) norm. Anisotropic estimates can be obtained by using the mollifiers technique. The restrictions of this approach is overcome by introducing some appropriate modification of the classical mollifiers procedure.
scientific article; zbMATH DE number 1675907