报告主题：符号图的流（Flows of signed graphs）
报告人：罗荣 教授 （West Virginia University,USA）
报告时间：2019年11月18日（周 一）15:00
报告地点：校本部G507
邀请人：康丽英 教授
主办部门：理学院数学系
报告摘要：
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.
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