Xuli Qi

activity

20132026

collaborators

8 papers

math.CO2026

Edge-chromatic $4$ -critical graphs and Overfull Conjecture for graphs with maximum degree $4$

Chunhui Ge, Gregory Gutin, Xuli Qi

Let $G$ be a simple graph with maximum degree $Δ (G)$ and chromatic index $χ^{'} (G)$ . A graph $G$ is called edge-chromatic $Δ$ -critical if $χ^{'} (G) = Δ (G) + 1$ and $χ^{'} (H) < χ^{'} (G)$ for every p…

math.CO2026

On distance spectral radius of power hypertrees with given number of pendant paths of fixed length

Yanna Wang, Xuli Qi

The distance spectral radius of a connected hypergraph is the largest eigenvalue of the distance matrix of the hypergraph. A pendant path of length l with l greater than or equal t…

math.CO2026

On the Hilton-Zhao vertex-splitting conjecture

Xuli Qi, Yanrui Feng

Let $G$ be a simple graph with order $n$ , maximum degree $Δ (G)$ , and chromatic index $χ^{'} (G)$ , respectively. A graph $G$ is edge-chromatic critical if $χ^{'} (H) < χ^{'} (G)$ for every proper…

math.CO2026

The average distance of spanning trees in terms of independence number

Zhibin Du, Xuli Qi

Let $G$ be a connected graph with vertex set $V (G)$ , and denote by $d_{G} (u, v)$ the distance from $u$ to $v$ in $G$ , for any $u, v \in V (G)$ . The average distance of an $n$ -vertex con…

math.CO2025

A new improvement to the Overfull Conjecture

Xuli Qi, Chunhui Ge, Yanrui Feng

Let $G$ be a simple graph with order $n$ , maximum degree $\D(G)$, minimum degree $δ (G)$ and chromatic index $χ^{'} (G)$ , respectively. A graph $G$ is called {\em $\D$-critical} if $χ'(…

math.CO2023

Bounds for eccentricity-based parameters of graphs

Yunfang Tang, Xuli Qi, Douglas B. West

The \emph{eccentricity} of a vertex $u$ in a graph $G$ , denoted by $e_{G} (u)$ , is the maximum distance from $u$ to other vertices in $G$ . We study extremal problems for the average e…

math.CO2022

Precoloring extension of Vizing's Theorem for multigraphs

Yan Cao, Guantao Chen, Guangming Jing +2

Let $G$ be a graph with maximum degree $Δ (G)$ and maximum multiplicity $μ (G)$ . Vizing and Gupta, independently, proved in the 1960s that the chromatic index of $G$ is at most $Δ(G)…

math.CO2013

The Kirchhoff indices and the matching numbers of unicyclic graphs

Xuli Qi, Bo Zhou, Zhibin Du

The Kirchhoff index of a connected graph is the sum of resistance distances between all unordered pairs of vertices in the graph. It found considerable applications in a variety of…

Edge-chromatic 4-critical graphs and Overfull Conjecture for graphs with maximum degree 4

On distance spectral radius of power hypertrees with given number of pendant paths of fixed length

On the Hilton-Zhao vertex-splitting conjecture

The average distance of spanning trees in terms of independence number

A new improvement to the Overfull Conjecture

Bounds for eccentricity-based parameters of graphs

Precoloring extension of Vizing's Theorem for multigraphs

The Kirchhoff indices and the matching numbers of unicyclic graphs

Edge-chromatic $4$ -critical graphs and Overfull Conjecture for graphs with maximum degree $4$