a_1x_1 + a_2x2 + ... + a_nx_n not zero when sum a_1=0,
Source: Austrian - Polish 1990 APMC
May 7, 2020
Sumalgebracombinatoricspartition
Problem Statement
is a sequence of integers such that every non-empty subsequence has non-zero sum. Show that we can partition the positive integers into a finite number of sets such that if all belong to the same set, then is non-zero.