How can i put letter on the top of each column of matrix?

Question

\documentclass{article}
\usepackage{amsmath,booktabs}
\begin{document}
[
\implies
\mathbf{B}^c=
\begin{bmatrix}
\begin{array}{@{}ccc|ccc|c@{}}
\mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0} & \mathbf{0} & \mathbf{0} \
\mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0} & \mathbf{0}\
 \mathbf{0} & \mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0}\
 \mathbf{0} & \mathbf{0} & \mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I}\
 \end{array}
 \end{bmatrix}
]
\end{document}

It would be helpful if you could put your MWE into once block that can be easily copy&pasted. — Matthias Arras, Oct 06 '20 at 15:01
@user224189 -- Can you say specifically why that link doesn't help/ — barbara beeton, Oct 07 '20 at 18:43

score 2 · Answer 1 · answered Oct 06 '20 at 18:46

With {pNiceArray} of nicematrix:

\documentclass{article}
\usepackage{amsmath,booktabs}
\usepackage{nicematrix}
\begin{document}
[
\mathbf{B}^c=
\begin{bNiceArray}{ccc|ccc|c}[first-row]
\mathbf{u}_c^{\mathbf{N}} & \mathbf{u}_e^{\mathbf{N}} & \mathbf{u}_o^{\mathbf{N}} 
& \mathbf{u}_c^{\mathbf{R}}&\mathbf{u}_e^{\mathbf{R}} & \mathbf{u}_o^{\mathbf{R}}
& \mathbf{u}_c^{\mathbf{OV}} \
\mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0} & \mathbf{0} & \mathbf{0} \
\mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0} & \mathbf{0}\
 \mathbf{0} & \mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I} & \mathbf{0}\
 \mathbf{0} & \mathbf{0} & \mathbf{0} & \mathbf{-I} & \mathbf{0} & \mathbf{0} & \mathbf{I}\
 \end{bNiceArray}
 ]
\end{document}

score 1 · Answer 2 · answered Oct 06 '20 at 16:36

Package blkarray can be your friend. An anexmple of it use (stolen from blkarray):

\documentclass{article}
\usepackage{blkarray}
\begin{document}
\[
\begin{blockarray}{ccccc}
      & A & B & C & D\\
    \begin{block}{c[cccc]}
    A & 1 & 1 & 1 & 1\\ 
    B & 1 & 0 & 0 & 1\\
    C & 1 & 0 & 1 & 1\\
    D & 1 & 1 & 1 & 0\\
    \end{block}
  \end{blockarray}
\]
\end{document}

You only need to replace cells' contents with your data and add missed columns in matrix.

How can i put letter on the top of each column of matrix?

2 Answers2