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I am reading this Wikipedia article on Kronecker product. How can I use LaTex to write this?

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  • 3
    Double click on the formula, and you can see the LaTeX-code. – hair-splitter Jun 11 at 9:57
  • 1
    Do try to familiarize yourself with the amsmath package, which provides an environment called bmatrix (short for "matrix surrounded by square brackets, I suppose). – Mico Jun 11 at 10:30
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Here's one possible way. I did it with stacks, since the row baselineskips can be tuned to make it work.

In general, (tab)stackengine constructs don't nest well, but in this case, I was able to make it work.

\documentclass{article}
\usepackage{tabstackengine}
\TABstackMath
\stackMath
\setstacktabbedgap{2ex}
\begin{document}
\[
\setstackgap{L}{1.2\normalbaselineskip}
  \bracketMatrixstack{1 & 2\\ 3 & 4}
  \otimes  
  \bracketMatrixstack{0 & 5\\ 6 & 7}
  =
  \left[\stackanchor{
    1\left[\Matrixstack{0&5\\6&7}\right]
    }{
    3\left[\Matrixstack{0&5\\6&7}\right]
  }
  \quad
  \stackanchor{
    2\left[\Matrixstack{0&5\\6&7}\right]
    }{
    4\left[\Matrixstack{0&5\\6&7}\right]
  }\right]
  =
  \bracketMatrixstack{
  1\times 0 & 1\times 5 & 2 \times 0 & 2 \times 5\\
  1\times 6 & 1\times 7 & 2 \times 6 & 2 \times 7\\
  3\times 0 & 3\times 5 & 4 \times 0 & 4 \times 5\\
  3\times 6 & 3\times 7 & 4 \times 6 & 4 \times 7
  }
  =
  \bracketMatrixstack{
  0 & 5 & 0 & 10\\
  6 & 7 & 12 & 14\\
  0 & 15 & 0 & 20\\
  18 & 21 & 24 & 28
  }
\]
\end{document}

enter image description here

2

I propose to use medium-sized matrices, as defined by the nccmath package, and bigstrut for fine-tuning the matrix brackets:

    \documentclass{article}
    \usepackage{amsmath, nccmath}
    \usepackage{bigstrut}
    \newenvironment{mbmatrix}{\begin{medsize}\begin{bmatrix}}{\end{bmatrix}\end{medsize}}

    \begin{document}

    \begin{align*}
   \begin{bmatrix}
    1 & 2 \\
    3 & 4
    \end{bmatrix}
    \otimes
    \begin{bmatrix}
    0 & 5 \\
     6 & 7
    \end{bmatrix}
    & =
  \begin{bmatrix}
    1 \begin{mbmatrix}
    0 & 5 \\
     6 & 7
    \end{mbmatrix}
     & 2\begin{mbmatrix}
    0 & 5 \\
     6 & 7
    \end{mbmatrix} \bigstrutjot=2ex \bigstrut[t] \\[1.5ex]
    3 \begin{mbmatrix}
    0 & 5 \\
     6 & 7
    \end{mbmatrix}
    & 4\begin{mbmatrix}
    0 & 5 \\
     6 & 7
    \end{mbmatrix} \bigstrutjot=2ex \bigstrut[b]
     \end{bmatrix}
     = \begin{bmatrix}
       1\times0 & 1\times5 & 2\times0 & 2\times5 \\
       1\times6 & 1\times7 & 2\times6 & 2\times7 \\
       3\times0 & 3\times5 & 4\times0 & 4\times5 \\
       3\times6 & 3\times7 & 4\times6 & 4\times7
     \end{bmatrix} \\
 & =\begin{bmatrix}
       0 & 5 & 0 & 10 \\
       6 & 7 & 12 & 14 \\
       0 & 15 & 0 & 20 \\
       18 & 21 & 24 & 28
     \end{bmatrix}
    \end{align*}

    \end{docume

enter image description here

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