 \displaystyle \frac{0}{n_0} \mathbf{0}_{G_0^\ast} \mathbf{0}^T_{G_0^\ast} & 0 & \cdots & 0\\ 0 & \displaystyle \frac{0}{n_0} \mathbf{0}_{G_0^\ast} \mathbf{0}^T_{G_0^\ast} & \cdots & 0\\ \vdots & \vdots & \ddots & \vdots \\ 0 & \cdots & 0 & \displaystyle \frac{0}{