Wednesday, December 20, 2017

What 's the short proof that for square matrices $AB = I$ implies $BA = I$?








I'm trying to remember the one line proof that for square matrices $AB = I$ implies $BA = I$.
I think it uses only elementary matrix properties and nothing else. Does anyone know the proof?



I remember it beginning with $BAB = B$ and the result following almost immediately.

No comments:

Post a Comment

analysis - Injection, making bijection

I have injection $f \colon A \rightarrow B$ and I want to get bijection. Can I just resting codomain to $f(A)$? I know that every function i...