For $A\in\mathbb F^{m\times n}$, $I_mA=A=AI_n$. The identity matrix has ones on the diagonal and zeros elsewhere, so it leaves every vector unchanged. The left and right identity matrices need not have the same size when $A$ is rectangular.
Parents
Like how this is organised?
Build your own knowledge tree on knowen.md: notes, decisions and tasks in one connected markdown graph, shared with your team and your AI agents.