MathDB
My best problem

Source: RMM 2020 Shortlist

October 15, 2021
algebra

Problem Statement

Let n>1n>1 be a positive integer and S\mathcal S be the set of nthn^{\text{th}} roots of unity. Suppose PP is an nn-variable polynomial with complex coefficients such that for all a1,,anSa_1,\ldots,a_n\in\mathcal S, P(a1,,an)=0P(a_1,\ldots,a_n)=0 if and only if a1,,ana_1,\ldots,a_n are all different. What is the smallest possible degree of PP?
Adam Ardeishar and Michael Ren