\begin{displaymath}\partial_{\eta} g(\eta(t),\varphi(t));
\end{displaymath}


\begin{displaymath}
U w V^\dagger
\end{displaymath}


\begin{displaymath}
\omega = h ( \eta , \varphi)
\end{displaymath}

$(I-D) \varphi(t)$ $\phi w V^t$ $h \dot \psi^\phi$