1 Erratum to: Bit Numer Math (2017) 57:329–350 DOI 10.1007/s10543-016-0633-x

Due to typing errors, the vector \(\mathbf {f}\) in (3.18) at p. 340 is wrong.

The correct vector is

$$\begin{aligned} \mathbf {f}:=\left[ \begin{array}{c} \mathbf {b} \\ \mathbf {a} \end{array} \right] . \end{aligned}$$