报告题目 (Title)：C_7的平面Turan数（Planar Turan number of C_7）
报告人 (Speaker)：郁星星 教授（美国佐治亚理工学院）
报告时间 (Time)：2023年5月22日(周一) 10:00
报告地点 (Place)：校本部F309
邀请人(Inviter)：谢齐沁
报告摘要：The planar Turan number of a graph H is the maximum number of edge in an n-vertex graph without H as a subgraph. We show that this number for C_7, the 7-cycle, is at most 18n/7 - 48/7, for n > 38, which is best possible for infinitely many n.