\begin{equation}
\frac{\delta ^{2}u\left( K,X,\Psi ,\hat{\Psi}\right) }{\delta \Psi \left(
K^{\prime },X\right) \delta \Psi ^{\dagger }\left( K^{\prime },X\right) }=-%
\frac{1}{\varepsilon }\hat{F}_{2}\left( s,R\left( K,X\right) \right) \hat{F}%
_{2}\left( s,R\left( K^{\prime },X^{\prime }\right) \right) \hat{K}_{X}
\label{duf}
\end{equation}%
