39 \(\begin{Bmatrix}u\\ \varphi\\ \end{Bmatrix}_{t+t}=\begin{Bmatrix}u\\ \varphi\\ \end{Bmatrix}_{t}-\begin{bmatrix}\mathbb{K}^{\text{uu}}&\mathbb{K}^{u\varphi}\\ \mathbb{K}^{\varphi u}&\mathbb{K}^{\text{φφ}}\\ \end{bmatrix}_{t}^{-1}\begin{Bmatrix}\mathbf{r}^{\mathbf{u}}\\ \mathbf{r}^{\varphi}\\ \end{Bmatrix}_{t},\)