Pairs of a tree and a nontree graph with the same status sequence
Abstract
The status of a vertex in a graph is the sum of the distances between and all other vertices. Let be a connected graph. The status sequence of is the list of the statuses of all vertices arranged in nondecreasing order. is called status injective if all the statuses of its vertices are distinct. Let be a member of a family of graphs and let the status sequence of be is said to be status unique in if is the unique graph in whose status sequence is In 2011, J.L. Shang and C. Lin posed the following two conjectures. Conjecture 1: A tree and a nontree graph cannot have the same status sequence. Conjecture 2: Any status injective tree is status unique in all connected graphs. We settle these two conjectures negatively. For every integer we construct a tree and a unicyclic graph both of order with the following two properties: (1) and have the same status sequence; (2) for if is congruent to modulo then is status injective and among any four consecutive even orders, there is at least one order such that is status injective.
Keywords
Cite
@article{arxiv.1901.09547,
title = {Pairs of a tree and a nontree graph with the same status sequence},
author = {Pu Qiao and Xingzhi Zhan},
journal= {arXiv preprint arXiv:1901.09547},
year = {2019}
}
Comments
14 pages, 11 figures