Some sufficient conditions for path-factor uniform graphs

Abstract

For a set $\mathcal{H}$ of connected graphs, a spanning subgraph $H$ of $G$ is called an $\mathcal{H}$-factor of $G$ if each component of $H$ is isomorphic to an element of $\mathcal{H}$. A graph $G$ is called an $\mathcal{H}$-factor uniform graph if for any two edges $e_1$ and $e_2$ of $G$, $G$ has an $\mathcal{H}$-factor covering $e_1$ and excluding $e_2$. Let each component in $\mathcal{H}$ be a path with at least $d$ vertices, where $d\ge 2$ is an integer. Then an $\mathcal{H}$-factor and an $\mathcal{H}$-factor uniform graph are called a $P_{\ge d}$-factor and a $P_{\ge d}$-factor uniform graph, respectively. In this article, we verify that (\romannumeral1) a 2-edge-connected graph $G$ is a $P_{\ge 3}$-factor uniform graph if $\delta (G)>\frac{\alpha (G)+4}{2}$; (\romannumeral2) a $(k+2)$-connected graph $G$ of order $n$ with $n\ge 5k+3-\frac{3}{5\gamma -1}$ is a $P_{\ge 3}$-factor uniform graph if $|N_G(A)|>\gamma (n-3k-2)+k+2$ for any independent set $A$ of $G$ with $|A|=\lfloor \gamma (2k+1)\rfloor$, where $k$ is a positive integer and $\gamma$ is a real number with $\frac{1}{3}\le \gamma \le 1$.

11 pages