English

Oriented trees in digraphs with large girth

Combinatorics 2025-09-23 v1

Abstract

The girth of a graph GG is the length of a shortest cycle of GG. Jiang (JCT-B, 2001) showed that every graph GG with girth at least 2+12\ell+1 and minimum degree at least k/k/\ell contains every tree TT with kk edges whose maximum degree does not exceed the minimum degree of GG. Let δ0(D)\delta^0(D) be the minimum semidegree of a digraph DD and Δ(D)\Delta(D) be the maximum degree of DD. In this paper, we establish a digraph version of Jiang's result, stating that every oriented graph DD of girth at least 2+12\ell+1 with δ0(D)max{k/,Δ(T)}\delta^0(D)\ge \max\{k/\ell,\Delta(T)\} contains every oriented tree with kk edges, that answers a question raised by Stein and Trujillo-Negrete in affirmative.

Keywords

Cite

@article{arxiv.2509.17756,
  title  = {Oriented trees in digraphs with large girth},
  author = {Junying Lu and Yaojun Chen},
  journal= {arXiv preprint arXiv:2509.17756},
  year   = {2025}
}

Comments

13 pages

R2 v1 2026-07-01T05:49:33.777Z