LaTeX Forum

\documentclass[11pt,ngerman]{article}
\usepackage[T1]{fontenc}
\usepackage{selinput}
\SelectInputMappings{
  adieresis={ä},
  germandbls={ß}
}
\usepackage{babel}
\usepackage{mathtools}

\begin{document}
  \begin{equation}
    \begin{pmatrix}
      \sigma_{11} & \sigma_{12} & \sigma_{13}\\
      \sigma_{21} & \sigma_{22} & \sigma_{23}\\
      \sigma_{31} & \sigma_{32} & \sigma_{33}\\
    \end{pmatrix}^\top
  \end{equation}
\end{document}

\begin{equation}
 \begin{bmatrix}
\sigma_{11} & \sigma_{12} & \sigma_{13}\\
\sigma_{21} & \sigma_{22} & \sigma_{23}\\
\sigma_{31} & \sigma_{32} & \sigma_{33}\\

\end{bmatrix}