The inspiration for this column comes not from the epic 1999 film The Matrix, as the title may suggest, but from an episode of Sean Carroll’s Mindscape podcast that I listened to over the summer. The ...

For a completely general partitioned matrix of the form $M = \begin{bmatrix}A & C\\R & D\end{bmatrix},$ a representation for (1)- and (1,2)-inverses of M is derived ...