Huajun Zhang

activity

20242026

collaborators

5 papers

math.CO2026

The ErdÅs-Ko-Rado Theorem in $ℓ_{2}$ -Norm

Biao Wu, Huajun Zhang

The codegree squared sum $co_{2} (F)$ of a family (hypergraph) $F \subseteq (k [ n ])$ is defined to be the sum of codegrees squared $d (E)^{2}$ over all $E\in \binom…

math.CO2025

On cross-2-intersecting families

Yanhong Chen, Anshui Li, Biao Wu +1

Two families $A \subseteq (k [ n ])$ and $B \subseteq (ℓ [ n ])$ are called cross- $t$ -intersecting if $∣ A \cap B ∣ \geq t$ for all $A \in A$ , $B\in\m…

math.CO2024

Non-uniform Cross-intersecting Families

Zhen Jia, Qing Xiang, Jimeng Xiao +1

Let $m \geq 2$ , $n$ be positive integers, and $R_{i} = {k_{i, 1} > k_{i, 2} > \dots > k_{i, t_{i}}}$ be subsets of $[n]$ for $i = 1, 2, \dots, m$ . The families $\mathcal{F}_1\subseteq \binom{[n]…

math.CO2024

Exact extremal non-trivial cross-intersecting families

Biao Wu, Huajun Zhang

Two families $A$ and $B$ of sets are called cross-intersecting if each pair of sets $A \in A$ and $B \in B$ has nonempty intersection. Let $\c…

math.CO2024

On a conjecture of Tokushige for cross- $t$ -intersecting families

Huajun Zhang, Biao Wu

Two families of sets $A$ and $B$ are called cross- $t$ -intersecting if $∣ A \cap B ∣ \geq t$ for all $A \in A$ , $B \in B$ . An active problem in extr…

The ErdÅs-Ko-Rado Theorem in ℓ2​-Norm

On cross-2-intersecting families

Non-uniform Cross-intersecting Families

Exact extremal non-trivial cross-intersecting families

On a conjecture of Tokushige for cross-t-intersecting families

The ErdÅs-Ko-Rado Theorem in $ℓ_{2}$ -Norm

On a conjecture of Tokushige for cross- $t$ -intersecting families