Cai-Hong Yang

collaborators

4 papers

math.CO2025

A hypergraph analogue of Alon-Frankl Theorem

Caihong Yang, Jiasheng Zeng, Xiao-Dong Zhang

Recently, Alon and Frankl (JCTB, 2024) determined the maximum number of edges in $K_{ℓ + 1}$ -free $n$ -vertex graphs with bounded matching number. For integers $ℓ \geq r \geq 2$ , t…

math.CO2025

Triple systems with bounded matching number: some constructions and exact Turán number

Nannan Chen, Miao Liu, Yuzhen Qi +1

We study the Turán numbers of $3$ -graphs avoiding $3$ -graphs $F$ and $M_{s + 1}^{3}$ , a matching of size $s + 1$ . We disprove a conjecture of Gerbner, Tompkins, and Zhou [European Journa…

math.CO2025

Generalized Turán results for disjoint copies of degenerate graphs

Caihong Yang, Jiasheng Zeng

The generalized Turán number $ex (n, H, F)$ denotes the maximum number of copies of $H$ in an $n$ -vertex $F$ -free graph. For an integer $t \geq 1$ , let $tF$ be the vertex-d…

math.CO2025

Exact Turán densities in triple systems

Nannan Chen, Yuzhen Qi, Caihong Yang +1

In this paper, we prove several new Turán density results for $3$ -graphs. We show: $π (C_{4}^{3}, complement of F_{5}) = 23 - 3$ , $π (F_{3, 2}, C_{5}^{3 -}) = \frac{2}{9}$ ,…