Distinct Lengths Modular Zero-sum Subsequences: A Proof of Graham's Conjecture

Weidong Gao, Y. O. Hamidoune, Guoqing Wang

Let $n$ be a positive integer and let $S$ be a sequence of $n$ integers in the interval $[0,n-1]$. If there is an $r$ such that any nonempty subsequence with sum $\equiv 0$ $\pmod…