MathDB
IMC 2011 Day 1 Problem 5

Source:

July 30, 2011
vectoralgebrapolynomialfunctionabstract algebraanalytic geometryinduction

Problem Statement

Let nn be a positive integer and let VV be a (2n1)(2n-1)-dimensional vector space over the two-element field. Prove that for arbitrary vectors v1,,v4n1V,v_1,\dots,v_{4n-1} \in V, there exists a sequence 1i1<<i2n4n11\leq i_1<\dots<i_{2n}\leq 4n-1 of indices such that vi1++vi2n=0.v_{i_1}+\dots+v_{i_{2n}}=0.