\[\mathbf{A}(z,\lambda)=\begin{bmatrix}\tfrac{1}{4}z&0\\
0&-\tfrac{1}{4}z\end{bmatrix}+\begin{bmatrix}-\tfrac{1}{2}\theta_{\infty}&u_{0%
}\\
u_{1}&\tfrac{1}{2}\theta_{\infty}\end{bmatrix}\dfrac{1}{\lambda}+\begin{%
bmatrix}v_{0}-\tfrac{1}{4}z&-v_{1}v_{0}\\
\ifrac{(v_{0}-\tfrac{1}{2}z)}{v_{1}}&\tfrac{1}{4}z-v_{0}\end{bmatrix}\frac{1}{%
\lambda^{2}},\]