MathDB
Functional Equations

Source: 2019 USAJMO 2, by Ankan

April 17, 2019
AMCUSA(J)MOUSAJMOfunctionalgebrafunctional equationHi

Problem Statement

Let Z\mathbb{Z} be the set of all integers. Find all pairs of integers (a,b)(a,b) for which there exist functions f ⁣:ZZf \colon \mathbb{Z}\rightarrow \mathbb{Z} and g ⁣:ZZg \colon \mathbb{Z} \rightarrow \mathbb{Z} satisfying f(g(x))=x+a  \text{and}  g(f(x))=x+b for all integers xx.
Proposed by Ankan Bhattacharya