Definition of a certain matrix

Question

I remember I came across matrix of the form

$$\begin{bmatrix} 1 & 0 & 0 & 0\\ 1 & 1 & 0 & 0\\ 0 & 1 & 1 & 0\\ 0 & 0 & 1 & 1\\ \end{bmatrix}$$

There is a name for it but I can't remember. Does anyone know the name of the matrix of this form?

Answer 1

It is called the Jordan Block .

$$\left(\begin{matrix} \lambda & 1 & 0 & \cdots & 0 \\ 0 & \lambda & 1 & \cdots & 0 \\ \vdots & \vdots & \vdots & \ddots & \vdots\\ 0 & 0 & 0 & \lambda & 1\\ 0 & 0 & 0 & 0 & \lambda \end{matrix}\right)$$