Fig. 8From: Convergence study of the h-adaptive PUM and the hp-adaptive FEM applied to eigenvalue problems in quantum mechanicsTreatment of hanging nodes for the h-adaptive PUM. \(Q_1\) denotes (bi)linear FE, whereas \(Q_{\mathrm{zero}}\) denotes elements on which functions in the FE space associated with the enrichment function \(f_k(\mathbf{x })\) are zero and thus no DoFs need to be introduced. a First FE space (standard). b Second FE space (enrichment)Back to article page