• <tr id='oJYMJV'><strong id='oJYMJV'></strong><small id='oJYMJV'></small><button id='oJYMJV'></button><li id='oJYMJV'><noscript id='oJYMJV'><big id='oJYMJV'></big><dt id='oJYMJV'></dt></noscript></li></tr><ol id='oJYMJV'><option id='oJYMJV'><table id='oJYMJV'><blockquote id='oJYMJV'><tbody id='oJYMJV'></tbody></blockquote></table></option></ol><u id='oJYMJV'></u><kbd id='oJYMJV'><kbd id='oJYMJV'></kbd></kbd>

    <code id='oJYMJV'><strong id='oJYMJV'></strong></code>

    <fieldset id='oJYMJV'></fieldset>
          <span id='oJYMJV'></span>

              <ins id='oJYMJV'></ins>
              <acronym id='oJYMJV'><em id='oJYMJV'></em><td id='oJYMJV'><div id='oJYMJV'></div></td></acronym><address id='oJYMJV'><big id='oJYMJV'><big id='oJYMJV'></big><legend id='oJYMJV'></legend></big></address>

              <i id='oJYMJV'><div id='oJYMJV'><ins id='oJYMJV'></ins></div></i>
              <i id='oJYMJV'></i>
            1. <dl id='oJYMJV'></dl>
              1. <blockquote id='oJYMJV'><q id='oJYMJV'><noscript id='oJYMJV'></noscript><dt id='oJYMJV'></dt></q></blockquote><noframes id='oJYMJV'><i id='oJYMJV'></i>

                图与组合系列讲座之五十九(宁博)

                发布时间:2020-11-03

                报告题目:Eigenvalues and triangles in graphs

                  : 宁博南开大学 教授)

                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

                欢迎各位】老师、同学届时前往!

                科学技术处

                2020年11月3日

                返回原图
                /