Finite element spaces by Whitney k-forms on cubical meshes
Shuo Zhang
TL;DR
The paper addresses constructing finite element spaces for $H$CusΛ^k$ on cubical meshes using Whitney $k$-forms to realize minimal-degree, locally supported spaces that still admit commuting interpolators and compatible discretizations. A nonconforming Whitney-based space $\boldsymbol{W}^{\rm def}_h\Lambda^k$ is introduced on cubical grids via a global constraint against the conforming tensor-product space and an adjoint projection $\mathbb{I}^{\mathbf{d}^k}_h$. The authors establish capacity and approximation properties, present a compatible discretization for $H\Lambda^k$ elliptic problems, and derive discrete de Rham complexes with commuting diagrams for $H\Lambda^k$. The framework is implementable using standard routines and sets the stage for extensions to adjoint problems, $H^*\Lambda^k$, and mixed cubical-simplicial meshes.
Abstract
Finite element spaces by Whitney $k$-forms on cubical meshes in $\mathbb{R}^n$ are presented. Based on the spaces, compatible discretizations to $HΛ^k$ problems are provided, and discrete de Rham complexes and commutative diagrams are constructed.
