Zhenyu Ni

activity

20152026

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12 papers · 1 filter

math.CO2026

Size Ramsey minimal graphs for uniform star forests

Pingting Fu, Zhidan Luo, Zhenyu Ni

For given graphs $G_{1}, G_{2}, \dots, G_{t}$ and $G$ , let $G \to (G_{1}, G_{2}, \dots, G_{t})$ denote that each $t$ -coloring of $E (G)$ yields a monochromatic copy of $G_{i}…

math.CO2026

Spectral Turán Problems for Expanded hypergraphs

Zhenyu Ni, Dongquan Cheng, Jing Wang +1

Given a graph $F$ , the expansion $F^{(r)}$ of $F$ is defined as the $r$ -uniform hypergraph obtained from $F$ by adding a set of $(r - 2)$ distinct new vertices to each edge of $F$ . I…

math.CO2025

Spectral extremal problems for degenerate graphs

Jiadong Wu, Liying Kang, Zhenyu Ni

A family of graphs is called degenerate if it contains at least one bipartite graph. In this paper, we investigate the spectral extremal problems for a degenerate family of graphs…

math.CO2024

Hypergraph Extensions of Spectral Turán Theorem

Lele Liu, Zhenyu Ni, Jing Wang +1

The spectral Turán theorem states that the $k$ -partite Turán graph is the unique graph attaining the maximum adjacency spectral radius among all graphs of order $n$ containing no t…

math.CO2023

Extremal problems for disjoint graphs

Zhenyu Ni, Jing Wang, Liying Kang

For a simple graph $F$ , let $EX (n, F)$ and $E X_{sp} (n, F)$ be the set of graphs with the maximum number of edges and the set of graphs with the maximum spectral ra…

math.CO2023

Spectral extremal graphs for edge blow-up of star forests

Jing Wang, Zhenyu Ni, Liying Kang +1

The edge blow-up of a graph $G$ , denoted by $G^{p + 1}$ , is obtained by replacing each edge of $G$ with a clique of order $p + 1$ , where the new vertices of the cliques are all distinc…

math.CO2022

Spectral extremal graphs for disjoint cliques

Zhenyu Ni, Jing Wang, Liying Kang

The $k K_{r + 1}$ is the union of $k$ disjoint copies of $(r + 1)$ -clique. Moon [Canad. J. Math. 20 (1968) 95--102] and Simonovits [Theory of Graphs (Proc. colloq., Tihany, 1996)] indep…

math.CO2022

Spectral Turán Type Problems on Cancellative Hypergraphs

Zhenyu Ni, Lele Liu, Liying Kang

Let $G$ be a cancellative $3$ -uniform hypergraph in which the symmetric difference of any two edges is not contained in a third one. Equivalently, a $3$ -uniform hypergraph $G$ is c…

math.CO2022

The maximal spectral radius of the uniform unicyclic hypergraph with perfect matchings

Rui Sun, Wen-Huan Wang, Zhen-Yu Ni

Let $U (n, k)$ and $Γ (n, k)$ be the set of the $k$ -uniform linear and nonlinear unicyclic hypergraphs having perfect matchings with $n$ vertices respectively, where $n\geq k…

math.CO2022

Extremal graphs for edge blow-up of lollipops

Yanni Zhai, Xiying Yuan, Zhenyu Ni

Given a graph $H$ and an integer $p$ ( $p \geq 2$ ), the edge blow-up $H^{p + 1}$ of $H$ is the graph obtained from replacing each edge in $H$ by a clique of order $(p + 1)$ , where the ne…

math.CO2021

Spectral extremal graphs for intersecting cliques

Dheer Noal Desai, Liying Kang, Yongtao Li +3

The $(k, r)$ -fan is the graph consisting of $k$ copies of the complete graph $K_{r}$ which intersect in a single vertex, and is denoted by $F_{k, r}$ . Erdős, Füredi, Gould and Gunderso…

math.CO2015

Matching criticality in intersecting hypergraphs

Liying Kang, Zhenyu Ni, Erfang Shan

A matching in a hypergraph $H$ is a set of pairwise vertex disjoint edges in $H$ and the matching number of $H$ is the maximum cardinality of a matching in $H$ . A transversal in $H…