On an inverse problem of Erd\H os, Kleitman, and Lemke
arXiv:2002.11811
Abstract
Let be a finite group and let $S=g_1\bdot \ldots\bdot g_{\ell}$ be a nonempty sequence over . We say is a tiny product-one sequence if its terms can be ordered such that their product equals and $\sum_{i=1}^{\ell}\frac{1}{\ord(g_i)}\le 1$. Let be the smallest integer such that every sequence over with has a tiny product-one subsequence. The direct problem is to obtain the exact value of , while the inverse problem is to characterize the structure of long sequences over which have no tiny product-one subsequences. In this paper, we consider the inverse problem for cyclic groups and we also study both direct and inverse problems for dihedral groups and dicyclic groups.