MathDB
2018 PAMO Shortlist: Players take turns choosing coefficients of a polynomial

Source: 2018 Pan-African Shortlist - C2

May 7, 2019
gamecombinatoricspolynomialinteger rootalgebra

Problem Statement

Adamu and Afaafa choose, each in his turn, positive integers as coefficients of a polynomial of degree nn. Adamu wins if the polynomial obtained has an integer root; otherwise, Afaafa wins. Afaafa plays first if nn is odd; otherwise Adamu plays first. Prove that:
[*] Adamu has a winning strategy if nn is odd. [*] Afaafa has a winning strategy if nn is even.