Lower Triangular Matrix/Examples/m less than n

Example of Lower Triangular Matrix
A lower triangular matrix of order $m \times n$ such that $m < n$:


 * $\mathbf L = \begin{bmatrix}

a_{1 1} &           0 &            0 & \cdots &                0 &       0 & \cdots &      0 &     0 \\ a_{2 1} &     a_{2 2} &            0 & \cdots &                0 &       0 & \cdots &      0 &     0 \\ a_{3 1} &     a_{3 2} &      a_{3 3} & \cdots &                0 &       0 & \cdots &      0 &     0 \\ \vdots &      \vdots &       \vdots & \ddots &           \vdots &  \vdots & \ddots & \vdots & \vdots \\ a_{m - 1, 1} & a_{m - 1, 2} & a_{m - 1, 3} & \cdots & a_{m - 1, m - 1} &      0 & \cdots &      0 &     0 \\ a_{m 1} &     a_{m 2} &      a_{m 3} & \cdots &     a_{m - 1, m} & a_{m m} & \cdots &      0 &     0 \\ \end{bmatrix}$