MathDB
Sum

Source: Canada 2000

March 4, 2006
combinatorics unsolvedcombinatorics

Problem Statement

Let A=(a1,a2,,a2000)A = (a_1, a_2, \cdots ,a_{2000}) be a sequence of integers each lying in the interval [1000,1000][-1000,1000]. Suppose that the entries in A sum to 11. Show that some nonempty subsequence of AA sums to zero.