“…Effective attempts are available, such as low-order finite difference or finite elements [4,6,10,11,22,23], and preconditioning differentiation by integration [7-9, 12, 13, 16, 20, 28, 29, 31]. In addition, suitable basis functions can be built from Birkhoff interpolation, and usually provide good appropriate preconditioners for usual collocation schemes, see [18,28,33,34].…”