Spectral radius and size conditions for fractional $(a,b,m)$-covered graphs

Abstract

A fractional $(a,b,m)$-covered graph is a generalization of the concept of a fractional $[a,b]$-covered graph. For any $H\subseteq G$ with edge set $|E(H)|=m$, if there exists a fractional $[a,b]$-factor (the corresponding fractional indicator function is $h$) such that $h(e)=1$ for any $e\in H$, then the graph $G$ is called a fractional $(a,b,m)$-covered graph. In this paper, we characterize the conditions for a graph to be a fractional $(a,b,m)$-covered graph from the perspectives of spectral radius and size, respectively.