_2 = \lambda_k\phi _{ij} = \lambda_k(\lambda_i\nabla^{\bot} \lambda_j -
\lambda_j\nabla^{\bot}\lambda_i).$$<p>Inside one triangle, we order the local bases in the following way:</p>
$$\{\phi_1,~\,\phi_2,~\,\phi_3,~\,\psi_1,~\,\psi_2,~\, \psi_3, ~\, \chi_1, ~\, \chi_2\}.$$<p>Note that $RT_0 \subset BDM_1 \subset RT_1$.</p>
<p>The first 3 dual bases are the line integral over orientated edges</p>
$$d_i^{\phi}(u) = \int_{e_i} u \cdot n_i \, ds,$$<p>and the second 3 dual bases are</p>
$$d_{ij}^{\psi}(u) = 3 \in