An improved upper bound for the planar Turán number of C₈

2026/07/17 by Xuqing Bai, Weichan Liu, Xiangxiang Nie +1
#math.CO #cs.DM

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Abstract

We prove that every n-vertex simple planar graph with no copy of C₈ has at most (69)/(25)(n-2) edges, for every n≥ 8. This improves the best known bound (323)/(108)n-6 for every n≥ 27.

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