# How to create asymetric matrix

I need to create this construction.

And I wrote this code

    \begin{equation*}
b_{12}^{(2)} =
\begin{array}{ccccccc}
1 & a & b & c & d &  & \\
a & 1 & \overline{e} & 0 & \overline{f} & & \\
\cline{1-5}
\vspace{-2ex} &&&&&& \\
a+ & a+ & b\overline{e}+ & 0+ & d\overline{f} & = &
\end{array}
\end{equation*}


• What is "not nice" about it? Is there some logic behind the "matrix addition"? – Werner Oct 24 '15 at 21:22

Some hand formatting:

\documentclass{article}
\usepackage{amsmath}
\usepackage{array,booktabs}

\newcommand{\splitcell}[2]{%
\begin{array}{@{}c@{}}
#1\\#2
\end{array}%
}

\begin{document}

$\setlength{\arraycolsep}{0pt} \begin{array}{ r<{{}} *{9}{>{{}}c<{{}}} } b_{12}^{(2)} = & \splitcell{1}{a} && \splitcell{a}{1} && \splitcell{b}{\bar{e}} && \splitcell{c}{0} && \splitcell{d}{\bar{f}} \\ \cmidrule{2-10} & a & + & a & + & b\bar{e} & + & 0 & + & d\bar{f} \end{array}$

\end{document}


I don't have access to an environment to test it at the moment, but this should work, I think: you can use the amsmath package's \genfrac command to stack two expressions with a line between them.

\genfrac{}{}{}{}{%
\begin{matrix}
1 & a & b & c & d\\
a & 1 & \bar{e} & 0 & \bar{f}
\end{matrix}%
}{a + a + b\bar{e} + 0 + d\bar{f}}


This will automatically produce the proper spacing.

• This is work, but in down string is small font – Ilia Ilin Oct 25 '15 at 7:55