Disjoint homometric sets in graphs

Abstract

Two subsets of vertices in a graph are called homometric if the multisets of distances determined by them are the same. Let h(n) denote the largest number h such that any connected graph of n vertices contains two disjoint homometric subsets of size h. It is shown that (c log n)/(log log n) < h(n) < n/4, for n > 3.