MathDB
Romanian National Olympiad 2018 - Grade 12 - problem 4

Source: Romania NMO - 2018

April 7, 2018
polynomialIrreduciblesuperior algebra

Problem Statement

For any kZ,k \in \mathbb{Z}, define Fk=X4+2(1k)X2+(1+k)2.F_k=X^4+2(1-k)X^2+(1+k)^2. Find all values kZk \in \mathbb{Z} such that FkF_k is irreducible over Z\mathbb{Z} and reducible over Zp,\mathbb{Z}_p, for any prime p.p.
Marius Vladoiu