\input{umtest-preamble} \usepackage[slash-delimiter=frac]{unicode-math} \setmathfont{Cambria Math} \begin{document} \[ \left.\left[\begin{array}{cc} a & b \\ c & d \end{array}\right] \middle/ \left[\begin{array}{cc} 1 & 1 \\ 1 & 0 \end{array}\right]\right. \] \end{document}