IMO 2006 Shortlist A4

Prove the inequality X i<j aiaj ai + aj ≤ n 2(a1 + a2 + ··· + an) X i<j aiaj for positive real numbers a1,a2,...,an. (Se...

IMO 2006 Shortlist A4

Category: Algebra

Problem

Prove the inequality X i<j aiaj ai + aj ≤ n 2(a1 + a2 + ··· + an) X i<j aiaj for positive real numbers a1,a2,...,an. (Serbia)