> Andrei wrote: > \usepackage{amsmath} > \begin{gather} > \begin{matrix} > -1&1&1 > 1&1&1 > \end{matrix} > \end{gather} One possibility should be: > \usepackage{amsmath} > \begin{gather} > \begin{matrix} > -1&1&1 > \hphantom{-}1&1&1 > \end{matrix} > \end{gather} Greetings, Juergen