Zero matrix
A matrix whose all columns are zero vectors,
\begin{equation*} 0 = \begin{pmatrix} \vphantom{\bigg(} \vec{0} & \vec{0} & \cdots \end{pmatrix}. \end{equation*}A matrix whose all columns are zero vectors,
\begin{equation*} 0 = \begin{pmatrix} \vphantom{\bigg(} \vec{0} & \vec{0} & \cdots \end{pmatrix}. \end{equation*}