\ProvidesPackage{mymath} \usepackage{euler} \usepackage{amssymb} \usepackage{amsmath} \usepackage{bbm} \newcommand{\matTT}[9]{ \[ \left|\begin{array}{ccc} #1 & #2 & #3\\ #4 & #5 & #6\\ #7 & #8 & #9 \end{array}\right| \] } \newcommand{\fork}[4]{ \left\{ \begin{array}{l l} #1 & \mbox{#2}\\ #3 & \mbox{#4}\\ \end{array} \right.} \newcommand{\forkthree}[6]{ \left\{ \begin{array}{l l} #1 & \mbox{#2}\\ #3 & \mbox{#4}\\ #5 & \mbox{#6}\\ \end{array} \right.} \newcommand{\vecthree}[3]{ \begin{bmatrix} #1\\ #2\\ #3 \end{bmatrix} } \newcommand{\vecthreethree}[9]{ \begin{bmatrix} #1 & #2 & #3\\ #4 & #5 & #6\\ #7 & #8 & #9 \end{bmatrix} }