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Flows and Group Connectivity of Graphs and Signed Graphs
【2018.1.9 10:00am, N613】

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 2017-12-22 

  Colloquia & Seminars 

  Speaker

罗荣 教授, 西弗吉尼亚大学

  Title

Flows and Group Connectivity of Graphs and Signed Graphs

  Time

2018.1.9 10:00-11:00

  Venue

N613

  Abstract

The concept of integer flows was introduced by Tutte as a generalization of map coloring and the concept of group connectivity was introduced by Jaeger, Linial, Payan, and Tarsi as a generalization of nowhere-zero group flows. Let A be an Abelian group. A-connected graphs are contractible configurations of A-flow and play an important role in the study of group flows because of the fact: if H is A-connected, then any supergraph G of H (i.e. G contains H as a subgraph) admits a nowhere-zero A-flow if and only if G/H does. In this talk I will survey some results on integer flows and group connectivity of ordinary graphs, and then introduce integer flows and group connectivity of signed graphs.  

  Affiliation

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。 

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