{ "id": "1302.1386", "version": "v2", "published": "2013-02-06T14:35:45.000Z", "updated": "2013-11-06T22:41:05.000Z", "title": "Homometric sets in trees", "authors": [ "Radoslav Fulek", "Slobodan Mitrović" ], "doi": "10.1016/j.ejc.2013.06.008", "categories": [ "math.CO" ], "abstract": "Let $G = (V,E)$ denote a simple graph with the vertex set $V$ and the edge set $E$. The profile of a vertex set $V'\\subseteq V$ denotes the multiset of pairwise distances between the vertices of $V'$. Two disjoint subsets of $V$ are \\emph{homometric}, if their profiles are the same. If $G$ is a tree on $n$ vertices we prove that its vertex sets contains a pair of disjoint homometric subsets of size at least $\\sqrt{n/2} - 1$. Previously it was known that such a pair of size at least roughly $n^{1/3}$ exists. We get a better result in case of haircomb trees, in which we are able to find a pair of disjoint homometric sets of size at least $cn^{2/3}$ for a constant $c > 0$.", "revisions": [ { "version": "v2", "updated": "2013-11-06T22:41:05.000Z" } ], "analyses": { "keywords": [ "disjoint homometric sets", "disjoint homometric subsets", "vertex sets contains", "haircomb trees", "disjoint subsets" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1302.1386F" } } }