deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index e093709..1306848 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
...
\end{bmatrix}  \end{equation}  The block matrix in the top left corner \begin{equation}  \begin{bmatrix}  2 & 0 \\  2 & I  \end{bmatrix}  =M_4  =\begin{matrix}  1 & 0 & 0 & 0 \\  1 & 1 & 0 & 0 \\  1 & 0 & 1 & 0 \\  1 & 1 & 0 & 1  \end{bmatrix}  \end{equation}