self-reversing is not nilpotence. In mathematics, a self-reversing function is called an involution, and it's f^2 (or f(f) ) = Id, the identity function. Nilp

self-reversing is not nilpotence. In mathematics, a self-reversing function is called an involution, and it's f^2 (or f(f) ) = Id, the identity function. Nilpotence is very different. It says that if you apply your function a certain number of times, you end up with zero no matter what the input is. For example, projection on x axis + 90 ° rotation of a vector is nilpotent.