yeah sorry i forgot a word
but that f can be written as a polynomial doen't exclude that it can be written in another form
for exmaple if f(f(f(x))) = x u have a lot of other possibilities
Hi can anyone help me please or give me a strong hint?
I have to prove this:
If f(x) is a function from natural to natural Numbers and f(f(f(x))) is stricly increasing a polynomial than f(x) is also.