ThmDex – An index of mathematical definitions, results, and conjectures.
Eigenvalue sequence for a diagonal complex matrix with constant diagonal
Formulation 0
Let $A \in \mathbb{C}^{N \times N}$ be a D6159: Complex square matrix such that
(i) $\lambda \in \mathbb{C}$ is a D1207: Complex number
(ii) \begin{equation} A = \begin{bmatrix} \lambda & 0 & \cdots & 0 \\ 0 & \lambda & \vdots & \vdots \\ \vdots & \cdots & \ddots & \vdots \\ 0 & \cdots & \cdots & \lambda \end{bmatrix} \end{equation}
Then $\lambda, \, \lambda, \, \ldots, \, \lambda$ is a D6192: Complex matrix eigenvalue sequence for $A$.
Subresults
R5568: Eigenvalue sequence for an identity complex matrix
Proofs
Proof 0
Let $A \in \mathbb{C}^{N \times N}$ be a D6159: Complex square matrix such that
(i) $\lambda \in \mathbb{C}$ is a D1207: Complex number
(ii) \begin{equation} A = \begin{bmatrix} \lambda & 0 & \cdots & 0 \\ 0 & \lambda & \vdots & \vdots \\ \vdots & \cdots & \ddots & \vdots \\ 0 & \cdots & \cdots & \lambda \end{bmatrix} \end{equation}
This result is a particular case of R5566: Eigenvalue sequence for a diagonal complex matrix. $\square$