deletions | additions       diff --git a/algorithm.tex b/algorithm.tex  index c1f8c94..6afed5e 100644  --- a/algorithm.tex  +++ b/algorithm.tex 
...
%% in which $\mZ(z)$ is the one-sided z-transform of $\mathbb{E}\{y(k) u(k)\}$  %in which $D=\begin{bmatrix} Q & 0 \\ 0 & R \end{bmatrix}$.  Since the feedback system is asymptotic stable, $\Phi_{y,u}(z)$ has no poles on the unit circle. Consider a Mobius transform $z=\frac{1+s}{1-s}$ and let $\Psi_{y,u}(s)=\Phi_{y,u}\left(\frac{1+s}{1-s}\right)$, then for $\Psi_{y,u}(s)$ there exists a positive real matrix $\mS(s)$ \cite{keith}, \cite{Keith},  such that \begin{equation} \label{Zdef}  \mS(s) + \mS^T(-s) = \Psi(s)=\mW(s)\mW^T(-s).  \end{equation}