“…Any multilevel basis for the one-particle space with a sufficient decay property may be used as basic ingredient for our sparse grid approach with similar results. Candidates are other hierarchical global polynomial systems [8,10,12,51,73] or function families with localization properties like wavelets [18], prewavelets [15,42], interpolets [19,22], and related wavelet-like constructs, see [12,16] for a survey. But also multiscale finite element systems and frames [37,40,41,67] or multiscale Gaussians [63] may be used 1,2 .…”