English

Connectivity keeping trees in triangle-free graphs

Combinatorics 2025-11-11 v1

Abstract

In 2012, Mader conjectured that for any tree TT of order mm, every kk-connected graph GG with minimum degree at least 3k2+m1\lfloor \frac{3k}{2}\rfloor+m-1 contains a subtree TTT'\cong T such that GV(T)G-V(T') remains kk-connected. In 2022, Luo, Tian, and Wu considered an analogous problem for bipartite graphs and conjectured that for any tree TT with bipartition (X,Y)(X,Y), every kk-connected bipartite graph GG with minimum degree at least k+max{X,Y}k+\max\{|X|,|Y|\} contains a subtree TTT'\cong T such that GV(T)G-V(T') remains kk-connected. In this paper, we relax the bipartite assumption by considering triangle-free graphs and prove that for any tree TT of order mm, every kk-connected triangle-free graph GG with minimum degree at least 2k+3m42k+3m-4 contains a subtree TTT' \cong T such that GV(T)G-V(T') remains kk-connected. Furthermore, we establish refined results for specific subclasses such as bipartite graphs or graphs with girth at least five.

Keywords

Cite

@article{arxiv.2511.06622,
  title  = {Connectivity keeping trees in triangle-free graphs},
  author = {Hojin Chu and Shinya Fujita and Boram Park and Homoon Ryu},
  journal= {arXiv preprint arXiv:2511.06622},
  year   = {2025}
}
R2 v1 2026-07-01T07:28:46.756Z