Hongzhang Chen

collaborators

8 papers

math.CO2026

Supersaturation in Nosal graphs: Triangles and books

Hongzhang Chen, Yongtao Li, Quanyu Tang

In this paper, we use the spectral surplus $I^» (G) - m$ to measure how far $G$ lies above the Nosal threshold, and prove the following edge-spectral supersaturation results f…

math.CO2026

An edge-spectral supersaturation of Mubayi's theorem for color-critical graphs

Hongzhang Chen, Yongtao Li

We study the supersaturation problem in its edge-spectral form. Let $I^» (G)$ be the adjacency spectral radius of $G$ . Nikiforov proved that every $K_{r + 1}$ -free graph $G$ with $m$ e…

math.CO2026

Spectral extremal graphs for even factors

Zeyuan Wu, Hongzhang Chen, Xinting Shi +1

An even factor of a graph $G$ is a spanning subgraph in which every vertex has positive even degree. It is known that the minimum degree $I^´ (G) \geq 2$ is a trivial necessary conditi…

math.CO2026

A non-hereditary Pollyanna class that is not strongly Pollyanna

Hongzhang Chen, Kaiyang Lan

Chudnovsky, Cook, Davies, and Oum introduced the notion of Pollyanna graph classes: a class $C$ is Pollyanna if for every $I ¨ $ -bounded class $F$ , the intersecti…

math.CO2026

On two conjectures of HoÃ ng

Hongzhang Chen, Kaiyang Lan, Wenlong Zhong

A graph $G$ is said to be perfectly divisible if for every induced subgraph $H$ of $G$ with at least one edge, the vertex set $V (H)$ can be partitioned into two sets $A, B$ such th…

math.CO2026

Counterexamples to a conjecture on graph inertia

Hongzhang Chen, Jianxi Li

The inertia of a graph $G$ is $In (G) = (n^{+} (G), n^{0} (G), n^{-} (G))$ , where $n^{+} (G), n^{0} (G), n^{-} (G)$ are the numbers of positive, zero and negative eigenvalues of the ad…