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