IMO 2020 Shortlist A2

Let A denote the set of all polynomials in three variables x,y,z with integer coefficients. Let B denote the subset of A...

IMO 2020 Shortlist A2

Category: Algebra

Problem

Let A denote the set of all polynomials in three variables x,y,z with integer coefficients. Let B denote the subset of A formed by all polynomials which can be expressed as px y zqPpx,y,zq pxy yz zxqQpx,y,zq xyzRpx,y,zq with P,Q,R P A. Find the smallest non-negative integer n such that xi yj zk P B for all non- negative integers i,j,k satisfying i j k ě n. (Venezuela)