<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">%%%------------------------------------------------------------------------------------------------------------
\begin{footnotesize}
$$
\begin{smallmatrix}  \underbrace{
    \left\{
        \begin{smallmatrix}
            \left[
            \begin{array}{cccc}
             1&amp; 0 &amp;0 \\
             0&amp; 1 &amp;0 \\
             0&amp; 0 &amp;1
            \end{array}
            \right ]
            \cdots
            \left[
            \begin{array}{cccc}
                1&amp; 0 &amp;0 \\
                0&amp; 1 &amp;0 \\
                0&amp; 0 &amp;1
            \end{array}
            \right]
        \end{smallmatrix}
        \right\}
     }\\5
\end{smallmatrix}
\times
\begin{smallmatrix}
\left[
    \begin{array}{cccc}
    1\\
    1\\
    1
    \end{array}
\right ]
\end{smallmatrix}
=
\begin{smallmatrix}  \underbrace{
    \left\{
        \begin{smallmatrix}
            \left[
            \begin{array}{cccc}
             1 \\
             1 \\
             1
            \end{array}
            \right ]
            \cdots
            \left[
            \begin{array}{cccc}
                1 \\
                1 \\
                1
            \end{array}
            \right]
        \end{smallmatrix}
        \right\}
     }\\5
\end{smallmatrix}
$$
\end{footnotesize}
%%%------------------------------------------------------------------------------------------------------------

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