Xiaoyu He

collaborators

7 papers

math.CO2025

Asymptotically half of binary words are shuffle squares

Xiaoyu He, Logan Post

A binary shuffle square is a binary word of even length that can be partitioned into two disjoint, identical subwords. Huang, Nam, Thaper, and the first author conjectured that as…

math.CO2025

New Sidorenko-type inequalities in tournaments

Xiaoyu He, Nitya Mani, Jiaxi Nie +2

As a directed analog of Sidorenko's conjecture in extremal graph theory, Fox, Himwich, Zhou, and the second author defined an oriented graph $H$ to be tournament Sidorenko (anti-Si…

math.CO2025

Ramsey numbers of grid graphs

Xiaoyu He, Ghaura Mahabaduge, Krishna Pothapragada +2

Let the grid graph $G_{M \times N}$ denote the Cartesian product $K_{M} □ K_{N}$ . For a fixed subgraph $H$ of a grid, we study the off-diagonal Ramsey number $\operatorname{gr}(H,…

math.CO2025

Polynomial-to-exponential transition in 3-uniform Ramsey numbers

Ruben Ascoli, Xiaoyu He, Hung-Hsun Hans Yu

Let $r_{k} (s, e; t)$ denote the smallest $N$ such that any red/blue edge coloring of the complete $k$ -uniform hypergraph on $N$ vertices contains either $e$ red edges among some $s$ …

math.CO2025

Off-Diagonal Ramsey Numbers for Linear Hypergraphs

Xiaoyu He, Jiaxi Nie, Yuval Wigderson +1

We study off-diagonal Ramsey numbers $r (H, K_{n}^{(k)})$ of $k$ -uniform hypergraphs, where $H$ is a fixed linear $k$ -uniform hypergraph and $K_{n}^{(k)}$ is complete on $n$ vertices. R…

math.CO2025

Generalized Erdős-Rogers problems for hypergraphs

Xiaoyu He, Jiaxi Nie

Given $r$ -uniform hypergraphs $G$ and $F$ and an integer $n$ , let $f_{F, G} (n)$ be the maximum $m$ such that every $n$ -vertex $G$ -free $r$ -graph has an $F$ -free induced subgraph on…