The existence of a $\{P_{2},C_{3},P_{5},\mathcal{T}(3)\}$-factor based on the size or the $A_α$-spectral radius of graphs

Xianglong Zhang, Lihua You

Published 2024-12-16, updated 2024-12-20Version 2

Let $G$ be a connected graph of order $n$. A $\{P_{2},C_{3},P_{5},\mathcal{T}(3)\}$-factor of $G$ is a spanning subgraph of $G$ such that each component is isomorphic to a member in $\{P_{2},C_{3},P_{5},\mathcal{T}(3)\}$, where $\mathcal{T}(3)$ is a $\{1,2,3\}$-tree. The $A_{\alpha}$-spectral radius of $G$ is denoted by $\rho_{\alpha}(G)$. In this paper, we obtain a lower bound on the size or the $A_{\alpha}$-spectral radius for $\alpha\in[0,1)$ of $G$ to guarantee that $G$ has a $\{P_{2},C_{3},P_{5},\mathcal{T}(3)\}$-factor, and construct an extremal graph to show that the bound on $A_{\alpha}$-spectral radius is optimal.