# How to typeset this matrix equation using simple LaTeX tools

Nest the second bmatrix as the first element of a matrix environment and add to the latter two empty rows:

\documentclass{article}

\usepackage{amsmath}

\begin{document}

\begin{equation*}
\begin{bmatrix}
\\
\; v\; \\
\\
\end{bmatrix}\!\!
\begin{matrix}
\begin{bmatrix}
\; w\; \\
\end{bmatrix}
\\{}\\ {}
\end{matrix}
\end{equation*}

\end{document}


Let TeX do the computations.

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{equation*}
A=
\vcenter{\hbox{\valign{\hbox{$#$}\vfil\cr
}}}
\end{equation*}

\end{document}


Perhaps nesting array-environments and \vphantom in some places does the trick—but I assume there are much better solutions.

\documentclass{article}
\usepackage{array}

\begin{document}
$A=\left[% \begin{array}{c}% {\vphantom{\left[\begin{array}{c}w\end{array}\right]}}\\ {v}\\ {\vphantom{\left[\begin{array}{c}w\end{array}\right]}}\\ \end{array}% \right]\mathclose{}\ % \kern-\arraycolsep \begingroup % Adjust \arraycolsep to regulate the horizontal gaps between "[" and "w" and "]" \arraycolsep=1\arraycolsep\relax \kern-\arraycolsep \begin{array}{c}% {\mathopen{}\left[\begin{array}{c}w\end{array}\right]}\\ {\vphantom{v}}\\ {\vphantom{\left[\begin{array}{c}w\end{array}\right]}}\\ \end{array}\kern-\arraycolsep\endgroup=A$
\end{document}