Xinyu Hu

activity

20242026

collaborators

7 papers

math.CO2026

A double-exponential lower bound for $r_{4} (5, n)$

Longma Du, Xinyu Hu, Ruilong Liu +1

The Ramsey number $r_{k} (s, n)$ is the smallest integer $N$ such that every $N$ -vertex $k$ -graph contains either a copy of $K_{s}^{(k)}$ or an independent set of size $n$ . We prove that…

math.CO2026

A Note on Generalized Erdős-Rogers Problems

Longma Du, Xinyu Hu, Ruilong Liu +1

For a $k$ -uniform hypergraph $F$ and positive integers $s$ and $N$ , the generalized Erdős-Rogers function $f_{F, s}^{(k)} (N)$ denotes the largest integer $m$ such that every $K_s^{(…

math.CO2026

A step towards the Erdős-Rogers problem

Longma Du, Xinyu Hu, Ruilong Liu +1

For $2 \leq k \leq t < s$ , the Erdős-Rogers function $f_{t, s}^{(k)} (N)$ denotes the largest $m$ such that every $K_{s}^{(k)}$ -free $k$ -graph on $N$ vertices contains a $K_{t}^{(k)}$ -free ind…

math.CO2026

Spectral bounds for the independence number of graphs and even uniform hypergraphs

Xinyu Hu, Jiang Zhou, Changjiang Bu

In this paper, we give spectral upper bounds for the independence number of even uniform hypergraphs and graphs, extend the Hoffman bound to even uniform hypergraphs, and give a si…

math.CO2025

Phase transitions of the Erdős-Gyárfás function

Xinyu Hu, Qizhong Lin, Xin Lu +1

Given positive integers $p, q$ . For any integer $k \geq 2$ , an edge coloring of the complete $k$ -graph $K_{n}^{(k)}$ is said to be a $(p, q)$ -coloring if every copy of $K_{p}^{(k)}$ receive…

math.CO2024

New bounds of two hypergraph Ramsey problems

Chunchao Fan, Xinyu Hu, Qizhong Lin +1

We focus on two hypergraph Ramsey problems. First, we consider the Erdős-Hajnal function $r_{k} (k + 1, t; n)$ . In 1972, Erdős and Hajnal conjectured that the tower growth rate of $r_k(k+…

A double-exponential lower bound for r4​(5,n)

A Note on Generalized Erdős-Rogers Problems

A step towards the Erdős-Rogers problem

Spectral bounds for the independence number of graphs and even uniform hypergraphs

Phase transitions of the Erdős-Gyárfás function

New bounds of two hypergraph Ramsey problems

A double-exponential lower bound for $r_{4} (5, n)$