题目：Flows of signed graphs
主讲人：西弗吉尼亚大学 罗荣 教授
时间：2019年11月15日(周五) 15:00~16:00
地点：A4-305
摘要：
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.
个人简介： 罗荣，西弗吉尼亚大学数学系教授。 主要研究领域是图的染色和流理论。 发表60多篇论文。
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