Template:U2dUniDiag

[math] U = \begin{bmatrix} 1 & u_{12} & 0 & \cdots & \cdots & 0 \\ 0 & 1 & u_{23}& \cdots & \cdots & 0 \\ 0 & 0 & 1 & \cdots & \cdots & 0 \\ \vdots & \vdots & \ddots & \ddots & \ddots & 0 \\ 0 & \cdots & \cdots & 0 & 1 & u_{n-1 n} \\ 0 & \cdots & \cdots & 0 & 0 & 1 \\ \end{bmatrix} [/math]