Fall 2017, problem 55
Let $f,g: \mathbb{N} \rightarrow \mathbb{N}$ such that $f(g(n)) = f(n) + 1$ and $g(f(n)) = g(n) + 1$. Show that $f = g$.
Let $f,g: \mathbb{N} \rightarrow \mathbb{N}$ such that $f(g(n)) = f(n) + 1$ and $g(f(n)) = g(n) + 1$. Show that $f = g$.