Yandong Bai

collaborators

6 papers

math.CO2026

Towards a strengthening of the second neighborhood conjecture

Yandong Bai, Binlong Li, Boram Park

A longstanding conjecture of Seymour, called Seymour's second neighborhood conjecture, states that every oriented graph $D$ contains a vertex $x$ with $|N^{++}_D(x)|\geq |N^{+}_D(x…

math.CO2026

Cycle lengths in graphs of given minimum degree

Yandong Bai, Andrzej Grzesik, Binlong Li +1

We prove that if $G$ is a 2-connected graph with minimum degree at least $k ⩾ 4$ , then (1) $G$ contains $k$ cycles whose lengths form an arithmetic progression with common d…

math.CO2026

Typical intersecting families are trivial

Yandong Bai, Haoyun Gu, Wenston J. T. Zang

We study the counting problem for non-uniform intersecting families in extremal set theory. Let $J (n, k)$ denote the number of intersecting families $F \subset 2^{[n]}$ suc…

math.CO2026

On 2-connected graphs without cycles of length 1 modulo 3

Yandong Bai, Hojin Chu, Binlong Li +2

Burr and ErdÅs conjectured in 1976 that for all integers $k > ℓ \geq 0$ such that $k Z + ℓ$ contains an even integer, every $n$ -vertex graph without cycles of length $\el…

math.CO2026

Cross-intersecting families with covering number constraints

Yandong Bai, Haoyun Gu

Two families $F$ and $G$ are cross-intersecting if every set in $F$ intersects every set in $G$ . The covering number $I ¨ (F)$ of a…

math.CO2025

On graphs without cycles of length 1 modulo 3

Yandong Bai, Binlong Li, Yufeng Pan +1

Burr and ErdÅs conjectured in 1976 that for every two integers $k > ℓ ⩾ 0$ satisfying that $k Z + ℓ$ contains an even integer, an $n$ -vertex graph containing no c…