题目 ：Average degrees of edge-chromatic critical graphs

报告人：刘慧清 教授（湖北大学）

时间：2017.11.17， 14:00-16:00

地点：数学系西大楼210

摘要：Given a graph G, denote by ∆,  and the maximum degree, the average degree and the chromatic index of G, respectively. A simple graph G is called edge-∆-critical if  and  for every proper subgraph H of G. Vizing in 1968 conjectured that if G is edge-∆-critical, then  In this talk, we show a result that improving the best known bound 2(∆+2)/3 obtained by Woodall in 2007 for ∆ ≥ 56. Additionally, Woodall constructed an infinite family of graphs showing his result cannot be improved by well-known Vizing’s Adjacency Lemma and other known edge-coloring techniques. To overcome the barrier, we follow the recoloring technique of Tashkinov trees to expand Vizing fans technique to a larger class of trees.

邀请人：陈耀俊 老师