学术报告
报告题目： Characterizing the extremal graphs with respect to the eccentricity eigenvalues, and beyond
报告人：李书超教授
报告时间：2020/11/23（周一）15:00-16:00
报告形式：腾讯会议(线上)数学学院A310(线下)
会议ID：955 523 398
会议密码：463782
报告摘要：
Given a graph G, the eccentricity matrix 
is constructed from the distance matrix of G by keeping only the largest nonzero elements for each row and each column and leaving zeros for the remaining ones. In this talk we first focus on some elementary and non-trivial properties on this novel matrix. Then we characterize the extremal graphs with respect to the eccentricity eigenvalues (including the largest and smallest eigenvalues). As a consequence, we solve two conjectures proposed by Wang et al. (2018). Furthermore, we study the -spectral determination of graphs. At last, for every , all graphs whose -spectra are contained in the interval are characterized.
报告人简介：
李书超，华中师范大学数学与统计学学院教授、博士生导师，信息与计算系主任。研究方向是组合数学、图论及其应用。先后在European Journal of Combinatorics, Journal of Algebraic Combinatorics, Journal of Combinatorial Designs、Journal of Combinatorial Optimization等国际SCI期刊发表学术论文100余篇，主持、参与国家自然科学基金多项。 2012主持完成的项目“图的几类重要不变量研究”获湖北省自然科学奖。