Changxiang He

activity

20172022

collaborators

7 papers

math.CO2022

Maximum principal ratio of the signless Laplacian of graphs

Lele Liu, Shengming Hu, Changxiang He

Let $G$ be a connected graph and $Q (G)$ be the signless Laplacian of $G$ . The principal ratio $γ (G)$ of $Q (G)$ is the ratio of the maximum and minimum entries of the Perron vector…

math.CO2022

Some multivariable Rado numbers

Gang Yang, Yaping Mao, Changxiang He +1

The Rado number of an equation is a Ramsey-theoretic quantity associated to the equation. Let $E$ be a linear equation. Denote by $R_{r} (E)$ the mi…

math.CO2021

Revisiting the Maximum Principal Ratio of Graphs

Lele Liu, Changxiang He

Let $G$ be a connected graph, the principal ratio of $G$ is the ratio of the maximum and minimum entries of its Perron eigenvector. In 2007, Cioab\v a and Gregory conjectured that…

math.CO2021

Some $α$ -spectral extremal results for some digraphs

Haiying Shan, Feifei Wang, Changxiang He

In this paper, we characterize the extremal digraphs with the maximal or minimal $α$ -spectral radius among some digraph classes such as rose digraphs, generalized theta digraphs an…

math.CO2020

A proof of a conjecture on the distance spectral radius and maximum transmission of graphs

Lele Liu, Haiying Shan, Changxiang He

Let $G$ be a simple connected graph, and $D (G)$ be the distance matrix of $G$ . Suppose that $D_{m a x} (G)$ and $λ_{1} (G)$ are the maximum row sum and the spectral radius of $D (G)$ , re…

math.CO2020

On the index of unbalanced signed bicyclic graphs

Changxiang He, Yuying Li, Haiying Shan +1

In this paper, we focus on the index ( largest eigenvalue) of the adjacency matrix of connected signed graphs. We give some general results on the index when the corresponding sign…