C = \left[ \begin{matrix} C_{00} & C_{01} & \cdots & C_{0k} \\ C_{10} & C_{11} & \cdots & C_{1k} \\ \vdots & \vdots & \ddots & \vdots \\ C_{k0} & C_{k1} & \cdots & C_{kk} \\ \end{matrix} \right]