ThmDex – An index of mathematical definitions, results, and conjectures.
Real square matrix which has a zero column or a zero row has determinant zero
Formulation 0
Let $A \in \mathbb{R}^{N \times N}$ be a D6160: Real square matrix such that
(i) $a_1, \ldots, a_N \in \mathbb{R}^{N \times 1}$ are each a D5200: Real column matrix
(ii) $b_1, \ldots, b_N \in \mathbb{R}^{1 \times N}$ are each a D5201: Real row matrix
(iii) \begin{equation} A = \begin{bmatrix} a_1 & a_2 & \cdots & a_N \end{bmatrix} \end{equation}
(iv) \begin{equation} A = \begin{bmatrix} b_1 \\ b_2 \\ \vdots \\ b_N \end{bmatrix} \end{equation}
Then
(1) \begin{equation} a_1 = \boldsymbol{0} \text{ or } a_2 = \boldsymbol{0} \text{ or } \cdots \text{ or } a_N = \boldsymbol{0} \quad \implies \quad \text{Det} A = 0 \end{equation}
(2) \begin{equation} b_1 = \boldsymbol{0} \text{ or } b_2 = \boldsymbol{0} \text{ or } \cdots \text{ or } b_N = \boldsymbol{0} \quad \implies \quad \text{Det} A = 0 \end{equation}
Proofs
Proof 0
Let $A \in \mathbb{R}^{N \times N}$ be a D6160: Real square matrix such that
(i) $a_1, \ldots, a_N \in \mathbb{R}^{N \times 1}$ are each a D5200: Real column matrix
(ii) $b_1, \ldots, b_N \in \mathbb{R}^{1 \times N}$ are each a D5201: Real row matrix
(iii) \begin{equation} A = \begin{bmatrix} a_1 & a_2 & \cdots & a_N \end{bmatrix} \end{equation}
(iv) \begin{equation} A = \begin{bmatrix} b_1 \\ b_2 \\ \vdots \\ b_N \end{bmatrix} \end{equation}