图与组合系列讲座之五十九

发布时间:2020-11-05

报告题目:Eigenvalues and triangles in graphs

: 宁博南开大学 教授)

报 告 摘 要:A well-known result in spectral graph theory states that a graph G on m edges has a triangle if the spectral radius $\lambda_1(G)>\sqrt{m}$. Bollob\'as and Nikiforov proposed a conjecture in 2007 that if $G$ is $K_{r+1}$-free then $\lambda_1^2+\lambda_2^2\leq \frac{k-1}{k}\cdot 2m$. We confirm this conjecture in the case of $r=2$ and find all extremal graphs for this case. Furthermore, we mention some other spectral results on triangles motivated by classical results due to Erd\H{o}s.

报告时间: 2020116(周五)  15:30-17:00

报告地点: 腾讯会议室:237-987-694

主办单位:  数学科学学学院

欢迎各位老师、同学届时前往!

                      科学技术处

2020115

  

 

 

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