A Polynomial Method Approach to Zero-Sum Subsets in ${\mathbb{F}}_p^2$

Abstract

In this paper we prove that every subset of ${\mathbb{F}}_p^2$ meeting all $p+1$ lines passing through the origin has a zero-sum subset. This is motivated by a result of Gao, Ruzsa and Thangadurai which states that $OL({\mathbb{F}}_p^2)=p+OL({\mathbb{F}}_p)-1$, for sufficiently large primes $p$. Here $OL(G)$ denotes the so-called Olson constant of the additive group $G$ and represents the smallest integer such that no subset of cardinality $OL(G)$ is zero-sum-free. Our proof is in the spirit of the Combinatorial Nullstellensatz.

6 pages; comments welcome!