Let $A \in \mathbb{C}^{N \times N}$ be a D6159: Complex square matrix such that

(i)	$A$ is a D5947: Triangular complex matrix

Let $z \in \mathbb{C}$ be a D1207: Complex number.

Then \begin{equation} \text{Det}(z I_N - A) = \prod_{n = 1}^N (z - A_{n, n}) \end{equation}