An improved upper bound for planar Turán number of double star $S_{2,5}$

Xin Xu, Yue Hu, Xu Zhang

The planar Turán number of a graph $H$, denoted by $e{x}_{\mathcal{P}}(n,H)$, is the maximum number of edges in an $n$-vertex $H$-free planar graph. Recently, D. Ghosh, et al. initia…