} \\ &\hspace{-0cm}= \begin{pmatrix} \mathbf{D}_{00} \tilde{\mathbf{F}}_{00} \mathbf{D}^\mathsf{T}_{00} & \mathbf{0}\\ \mathbf{0} & \mathbf{D}_{00} \tilde{\mathbf{F}}_{00} \mathbf{D}^\mathsf{T}_{00}\\ \end{pmatrix}.\end{aligned}$$ This means that the 