Cun-Xiang Duan

activity

20172026

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6 papers · 1 filter

math.CO2026

Spectral Extremal Graphs without a $K_{k}$ -Factor

Cunxiang Duan, Tingting Han, Lin-Peng Zhang

Let $k \geq 3$ and let $n = k m$ . A $K_{k}$ -factor in an $n$ -vertex graph is a collection of $m$ vertex-disjoint copies of $K_{k}$ that covers the entire vertex set. We determine the maximu…

math.CO2025

The characteristic polynomials of $r$ -uniform hypercycles with length $l$

Dong Bo, Duan Cunxiang, Wang Ligong

Let $C_{l}$ be a cycle with length $l .$ The $r$ -uniform hypercycle with length $l$ is obtained by adding $r - 2$ new vertices in every edge of $C_{l},$ denoted by $C_{l}^{(r)}$ . In thi…

math.CO2022

Signless Laplacian Estrada index and Laplacian Estrada index of uniform hypergraphs

Cunxiang Duan, Edwin R. van Dam, Ligong Wang

We generalize the notions of Laplacian and signless Laplacian Estrada index to uniform hypergraphs. For an $r$ -uniform hypergraph $H,$ we derive an order $r + 1$ trace formula of the…

math.CO2020

The bounds of the spectral radius of general hypergraphs in terms of clique number

Cunxiang Duan, Ligong Wang

The spectral radius (or the signless Laplacian spectral radius) of a general hypergraph is the maximum modulus of the eigenvalues of its adjacency (or its signless Laplacian) tenso…

math.CO2018

The largest signless Laplacian spectral radius of uniform supertrees with diameter and pendent edges (vertices)

Cunxiang Duan, Ligong Wang, Peng Xiao

Let $S_{1} (m, d, k)$ be the $k$ -uniform supertree obtained from a loose path $P : v_{1}, e_{1}, v_{2}, \dots, v_{d}, e_{d}, v_{d + 1}$ with length $d$ by attaching $m - d$ edges at verte…

math.CO2017

Edge Connectivity, Packing Spanning Trees, and Eigenvalues of Graphs

Cunxiang Duan, Ligong Wang, Xiangxiang Liu

Let $G$ be the set of simple graphs (or multigraphs) $G$ such that for each $G \in G$ there exists at least two non-empty disjoint proper subsets $V_{1},V_{2}\s…