Let $A \in \mathbb{R}^{N \times M}$ be a
D4571: Real matrix such that
| (i) |
\begin{equation}
A
=
\begin{bmatrix}
A_{1, 1} & A_{1, 2} & \cdots & A_{1, M} \\
A_{2, 1} & A_{2, 2} & \vdots & A_{2, M} \\
\vdots & \cdots & \ddots & \vdots \\
A_{N, 1} & A_{N, 2} & \cdots & A_{N, M}
\end{bmatrix}
\end{equation}
|
The
vectorization of $A$ is the
D5200: Real column matrix
\begin{equation}
\begin{bmatrix}
A_{1, 1}, & \ldots, & A_{N, 1}, & A_{1, 2}, & \ldots, & A_{N, 2}, & \ldots, & A_{1, M}, & \ldots, & A_{N, M}
\end{bmatrix}
^T
\in \mathbb{R}^{NM \times 1}
\end{equation}
