Given a full column rank matrix $A \in \mathbb{R}^{n\times m}$. The left pseudo-inverse is $A_{\text{left}}^{-1}=(A^\top A)^{-1}A^{\top}$. Then we have the following relationship $$\|A_{\text{left}}^{-1}\|_2=\frac{1}{\sigma_{\text{min}(A)}}$$.
I have seen this question , and there is also an online problem set that contains this problem. My question is: Where does this problem come from? I want to know whether it is from a certain book so that I can cite it in a proper way.
Thank you very much for your help!!