答案1
以下是代码blkarray
:
\documentclass[12pt]{article}
\usepackage{amsmath}
\usepackage{bigstrut}
\usepackage{blkarray}
\begin{document}
\[
\bigstrutjot=0.8ex\begin{blockarray}{cccc}%
& &|V| \\
\begin{block}{c[ccc]}
\bigstrut[t] \\ |V| & & X & \\ \bigstrut \\
\end{block}
\end{blockarray}
= \begin{blockarray}{ccc@{\:}c}%
& &|V| \\
\begin{block}{c[cc@{\:}c]}
&{} \mid{}\bigstrut[t] & \vert \\ |V| & u_1 & u_2 & \dotsb \\ & \vert & \vert\bigstrut \\
\end{block}
\end{blockarray}
\begin{blockarray}{cccc}%
& &|V| \\
\begin{block}{c[cc@{\:}c]}
& \sigma_1 & 0 & \dotsb \bigstrut[t] \\ |V| & 0 & \sigma_2 & \dotsb \\ & \vdots & \vdots & \ddots\bigstrut[b] \\
\end{block}
\end{blockarray}
\begin{blockarray}{cc@{\:}cc}%
& &|V| \\
\begin{block}{c[c@{\enspace}c@{\:}c]}
& {}\relbar & v_1 & \relbar\bigstrut[t] \\ |V| & {}\relbar & v_2 & \relbar \\ & & \vdots &\bigstrut[b] \\
\end{block}
\end{blockarray}
\]
\end{document}