English

On majorization of closed walks vector of trees with given degree sequences

Combinatorics 2018-06-05 v1

Abstract

Let Cv(k;T)C_{v}(k;T) be the number of the closed walks of length kk starting at vertex vv in a tree TT. We prove that for a given tree degree sequence π\pi, then for any tree with degree sequence π\pi, the sequence C(k;T)(Cv(k;T),vV(T))C(k;T)\equiv(C_{v}(k;T), v\in V(T)) is weakly majorized by the sequence C(k,Tπ)C(k,Tπ,vV(T))C(k, T_{\pi}^*)\equiv C(k, T_{\pi}^*, v\in V(T^*)), where TπT_{\pi}^* is the greedy tree corresponding to π\pi. In addition, for two trees degree sequences π, π\pi,~\pi', if π\pi is majorized by π\pi', then C(k;Tπ)C(k;T_{\pi}^*) is weakly majorized by C(k;Tπ)C(k;T_{\pi'}^*).

Keywords

Cite

@article{arxiv.1806.00789,
  title  = {On majorization of closed walks vector of trees with given degree sequences},
  author = {Ya-Hong Chen and Daniel Gray and Ya-Lei Jin and Xiao-Dong Zhang},
  journal= {arXiv preprint arXiv:1806.00789},
  year   = {2018}
}

Comments

16 pages 2 figures, Applied Mathematics and Computation, 2018