English

Constructing new families of transmission irregular graphs

Combinatorics 2020-04-20 v1

Abstract

The transmission of a vertex vv of a graph GG is the sum of distances from vv to all the other vertices in GG. A graph is transmission irregular if all of its vertices have pairwise different transmissions. A starlike tree T(k1,,kt)T(k_1,\ldots,k_t) is a tree obtained by attaching to an isolated vertex tt pendant paths of lengths k1,,ktk_1,\ldots,k_t, respectively. It is proved that if a starlike tree T(a,a+1,,a+k)T(a,a+1,\ldots,a+k), k2k\ge 2, is of odd order, then it is transmission irregular. T(1,2,,)T(1,2,\ldots,\ell), 3\ell \ge 3, is transmission irregular if and only if {r2+1: r2}\ell \notin \{r^2 + 1:\ r\ge 2\}. Additional infinite families among the starlike trees and bi-starlike trees are determined. Transmission irregular unicyclic infinite families are also presented, in particular, the line graph of T(a,a+1,a+2)T(a,a+1,a+2), a2a\ge 2, is transmission irregular if and only if aa is even.

Keywords

Cite

@article{arxiv.2004.08093,
  title  = {Constructing new families of transmission irregular graphs},
  author = {Kexiang Xu and Sandi Klavžar},
  journal= {arXiv preprint arXiv:2004.08093},
  year   = {2020}
}
R2 v1 2026-06-23T14:54:54.413Z