Yanbo Zhang

collaborators

9 papers

math.CO2026

ErdÅs--Ko--Rado theorems in $ℓ_{2}$ -norm for three finite spaces

Qian Bao, Yaojun Chen, Yanbo Zhang

Let $F$ be a $k$ -uniform hypergraph. The famous ErdÅs--Ko--Rado (1961) theorem determines the maximum size and extremal structure for $F$ being $t$ -intersectin…

math.CO2026

A note on tree-cycle Ramsey numbers

Ting Huang, Yanbo Zhang, Yaojun Chen

Let $R (T_{n}, C_{m})$ denote the Ramsey number of a tree $T_{n}$ on $n$ vertices versus a cycle $C_{m}$ of length $m$ . Burr, ErdÅs, Faudree, Rousseau, and Schelp (1982) asked for the least…

math.CO2026

Online Ramsey numbers of the claw versus cycles

Hexuan Zhi, Yanbo Zhang

The online Ramsey number $r ~ (G, H)$ is defined via a Builder--Painter game on an empty graph with countably many vertices. In each round, Builder reveals an edge, which Painte…

math.CO2025

Trichotomy and $t K_{m}$ -goodness of sparse graphs

Yanbo Zhang, Yaojun Chen

Let $G$ be a connected graph with $n$ vertices and $n + k - 2$ edges and $t K_{m}$ denote the disjoint union of $t$ complete graphs $K_{m}$ . In this paper, by developing a trichotomy for sp…

math.CO2025

Ramsey goodness of stars and fans for the HajÃ³s graph

Jiafu He, Haiyu Zeng, Yanbo Zhang

Given two graphs $G_{1}$ and $G_{2}$ , the Ramsey number $R (G_{1}, G_{2})$ denotes the smallest integer $N$ such that any red-blue coloring of the edges of $K_{N}$ contains either a red $G_{1}$ …

math.CO2025

Fan-goodness of sparse graphs

Ting Huang, Yanbo Zhang, Yaojun Chen

Let $G$ be a connected graph of order $n$ , $F_{k}$ be a fan consisting of $k$ triangles sharing a common vertex, and $t F_{k}$ be $t$ vertex-disjoint copies of $F_{k}$ . Brennan (2017) sho…

ErdÅs--Ko--Rado theorems in ℓ2​-norm for three finite spaces

A note on tree-cycle Ramsey numbers

Online Ramsey numbers of the claw versus cycles

Trichotomy and tKm​-goodness of sparse graphs

Ramsey goodness of stars and fans for the HajÃ³s graph

Fan-goodness of sparse graphs

ErdÅs--Ko--Rado theorems in $ℓ_{2}$ -norm for three finite spaces

Trichotomy and $t K_{m}$ -goodness of sparse graphs