Abstract :
In this paper we consider the following open problems: Conjecture 0.1. Let S be a sequence of 3n−3 elements in Cncircled plusCn. If S contains no nonempty zero-sum subsequence of length not exceeding n, then S consists of three distinct elements, each appearing n−1 times. Conjecture 0.2. Let S be a sequence of 4n−4 elements in Cncircled plusCn. If S contains no zero-sum subsequence of length n, then S consists of four distinct elements, each appearing n−1 times. We show that both Conjecture 0.1 and Conjecture 0.2 are multiplicative, i.e., if Conjecture 0.1 (Conjecture 0.2) holds both for n=k and n=l then it holds also for n=kl.
