Problem

Source: Balkan MO Shortlist 2013 A7 BMO

Tags: composition, algebra, mapping, bijection, bijective function, positive integers



Suppose that $k$ is a positive integer. A bijective map $f : Z \to Z$ is said to be $k$-jumpy if $|f(z) - z| \le k$ for all integers $z$. Is it that case that for every $k$, each $k$-jumpy map is a composition of $1$-jumpy maps? It is well known that this is the case when the support of the map is finite.