\begin{eqnarray*}
  \label{eq:ztBar}
%    \bar{\mathbf{z}}_{t} & = & \mathbf{z}_{t} \\
    \bar{\mathbf{z}}_{t+1} & = & \mathbf{E}_{t}[\mathbf{z}_{t+1}] = \mathbf{z}_{t}
\\ \ifnumber  \vdots &  & \vdots \nonumber
\\ \ifnumber  \bar{\mathbf{z}}_{t+n-1} & = & \mathbf{E}_{t}[\mathbf{z}_{t+n-1}] = \mathbf{z}_{t}
\end{eqnarray*}
