3 papers
math.CO2026
An improved upper bound for the planar Turán number of
Xuqing Bai, Weichan Liu, Xiangxiang Nie +1
We prove that every -vertex simple planar graph with no copy of has at most \[ \frac{69}{25}(n-2) \] edges, for every . This improves the best known bound \[ \frac…
math.CO2025
Planar Turán numbers of three configurations
Xuqing Bai, Zhipeng Gao, Ping Li
The planar Tuán number of , denoted by , is defined as the maximum number of edges in an -vertex -free planar graph. The exact value of $ex_{\mathca…
math.CO2024
Cooperative colorings of hypergraphs
Xuqing Bai, Bi Li, Weichan Liu +1
Given a class of hypergraphs with the same vertex set , a cooperative coloring of them is a partition …