讲座题目：Flows of signed graphs 主讲人🙍🏽♂️：Prof.Rong Luo 主持人：吕长虹 教授 开始时间：2019-11-19 13:00:00 讲座地址：闵行数学楼402 主办单位🏌🏻♀️：数学科学学院
报告人简介🎮： 罗荣，美国西弗吉尼亚大学（West Virginia University★，USA）数学系教授💢。主要研究图的染色理论和流的理论🧑🏿🦲，是国际知名的染色问题专家👍🏿。发表近50余篇论文，多数是发表在图论顶尖杂志如Journal of Cominatorial Theory Ser. B, Journal of Graph Theory, SIAM Journal on Discrete Math, and European J. of Combinatorics. 在Vizing上世纪60年代末提出的四个关于边染色的猜想取得了一系列突破性进展。解决了几个著名公开问题如Erdos🚝、Gould Jacobson以及 Lehel提出的一个关于可图序列猜想🕵🏻♀️，Borodin提出的边面染色的问题，以及Archdeacon关于三流可图序列的问题。 报告内容： It was observed by Tutte that the problem of the face-coloring (map coloring) of a graph embedded on an orientable surface can be formulated in terms of integer flows of the graph. It was further extended by Bouchet (JCTB 1983) for graphs on non-orientable surfaces. For graphs embedded on non-orientable surfaces, the dual version of vertex-coloring is the flow problem for signed graphs. An edge is negative if it passes through an odd number of crosscaps. Bouchet (JCTB 1983) conjectured that every flow admissible signed graph admits a nowhere-zero 6-flow. In this talk, I will report the progresses we make toward Bouchet’s 6-flowo conjecture. |
