- $$ \left[ \begin{array}{cccc} + & 0 & 1 &2 & 3 \\ \hline 0 & 0 & 1 &2 & 3 \\ 1 & 1 & 2 &3 & 0 \\ 2 & 2 & 3 &0 & 1 \\ 3 & 3 & 0 &1 & 2 \end{array} \right] .$$
$${\mathbf{R}} =\left[ R_{ij} \right] = \left[ \begin{array}{cccc}R_{11} & R_{12} & \cdots & R_{1N} \\ R_{21} & R_{22}& \cdots & R_{2N} \\ \cdots & \cdots & \cdots &\cdots \\ R_{N1} & R_{N2} & \cdots & R_{NN} \end{array} \right] .$$
$$\begin{tabular}{c} + & 0 & 1 & 2 & 3 \\\hline 0 & 0 & 1 & 2 & 3 \\ 1 & 1 & 2 & 3 & 0 \\ 2 & 2 & 3 & 0 & 1 \\ 3 & 3 & 0 & 1 & 2 \\ \end{tabular}$$ $$\begin{tabular}{c|cccccc} + & 0 & 1 & 2 & 3 \\\hline 0 & 0 & 1 & 2 & 3 \\ 1 & 1 & 2 & 3 & 0 \\ 2 & 2 & 3 & 0 & 1 \\ 3 & 3 & 0 & 1 & 2 \\ \end{tabular}$$
$$\begin{tabular}{c} {\rm Operationen } \\ {\rm modulo}\hspace{0.15cm}{\it q} = 4\\ \end{tabular}\hspace{0.25cm} \Rightarrow\hspace{0.25cm} \begin{tabular}{c|cccccc} + & 0 & 1 & 2 & 3 \\\hline 0 & 0 & 1 & 2 & 3 \\ 1 & 1 & 2 & 3 & 0 \\ 2 & 2 & 3 & 0 & 1 \\ 3 & 3 & 0 & 1 & 2 \\ \end{tabular} &\hspace{0.25cm} \begin{tabular}{c|cccccc} $\cdot$ & 0 & 1 & 2 & 3 \\\hline 0 & 0 & 0 & 0 & 0 \\ 1 & 0 & 1 & 2 & 3 \\ 2 & 0 & 2 & 0 & 2 \\ 3 & 0 & 3 & 2 & 1 \\ \end{tabular} \hspace{0.05cm}. $$
