English

Component factors in $K_{1,r}$-free graphs

Combinatorics 2020-12-14 v1

Abstract

A graph is said to be K1,rK_{1,r}-free if it does not contain an induced subgraph isomorphic to K1,rK_{1,r}. An F\mathcal{F}-factor is a spanning subgraph HH such that each connected component of HH is isomorphic to some graph in F\mathcal{F}. In particular, HH is called an {P2,P3}\{P_2,P_3\}-factor of GG if F={P2,P3}\mathcal{F}=\{P_2,P_3\}; HH is called an Sn\mathcal{S}_n-factor of GG if F={K1,1,K1,2,K1,3,...,K1,n}\mathcal{F}=\{K_{1,1},K_{1,2},K_{1,3},...,K_{1,n}\}, where n2n\geq2. A spanning subgraph of a graph GG is called a Pk\mathcal{P}_{\geq k}-factor of GG if its each component is isomorphic to a path of order at least kk, where k2k\geq2. A graph GG is called a F\mathcal{F}-factor covered graph if there is a F\mathcal{F}-factor of GG including ee for any eE(G)e\in E(G). In this paper, we give a minimum degree condition for a K1,rK_{1,r}-free graph to have an Sn\mathcal{S}_n-factor and a P3\mathcal{P}_{\geq 3}-factor, respectively. Further, we obtain sufficient conditions for K1,rK_{1,r}-free graphs to be P2\mathcal{P}_{\geq 2}-factor, P3\mathcal{P}_{\geq 3}-factor or {P2,P3}\{P_2,P_3\}-factor covered graphs. In addition, examples show that our results are sharp.

Keywords

Cite

@article{arxiv.2012.06359,
  title  = {Component factors in $K_{1,r}$-free graphs},
  author = {Guowei Dai and Zan-Bo Zhang and Xiaoyan Zhang},
  journal= {arXiv preprint arXiv:2012.06359},
  year   = {2020}
}

Comments

13 pages

R2 v1 2026-06-23T20:54:09.219Z