# How can I typeset the following nested matrices? Note that it has to be square brackets. The big A can be normal size if necessary as long as it's still centered on the left. I could also live with it being below the outer matrix annotating the left hand side with curly braces.

• Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}. • Note this is a Q&A site, not a please do this for me service. What do you have so far. – albert Dec 11 '18 at 18:52

Something like this?

\documentclass{article}
\usepackage{amsmath,graphicx,arydshln}

\begin{document}

\begin{equation*}
\left[
\begin{array}{ @{} c c : c c @{} }
\hphantom{\ddots}
&
\left[
\begin{array}{ @{} ccc @{}}
\phantom{1} \\ & \phantom{1} \\ && \phantom{1}
\end{array}
\right.
&
\left.
\begin{array}{ @{} ccc @{}}
1 \\ & 1 \\ && 1
\end{array}
\right]
\\
\multicolumn{2}{c:}{\makebox[0pt]{\smash{\scalebox{5}{A}}}} && \ddots
\end{array}
\right]
\end{equation*}

\end{document} After replacing \multicolumn{2}{c:}{...} by

\multicolumn{2}{c:}{\makebox[0pt]{\raisebox{.2\height}[0pt][0pt]{\scalebox{5}{A}}}}


the output will be The amount of raising has been guessed. It may be computed, but I don't think you need such an object more than once.

• This is really good. I didn't think of using \left[, \right[, and arrays at all. Though, can you also think of a way to center the A vertically? – Sebastian Oberhoff Dec 12 '18 at 1:16
• @SebastianOberhoff Added. – egreg Dec 12 '18 at 8:33