1. ## projections

Let $\pi:V\to V$ be a linear transformation satisfying $\pi^2=\pi$. Prove that Pi is a projection of V onto the Image of Pi along the ker of Pi.

I have no idea but I am guessing the idempotent property is important.

2. ## Re: projections

Originally Posted by dwsmith
I have no idea but I am guessing the idempotent property is important.
You could, say that, it's eqiuvalent to being a projection. What have you tried?