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王维凡教授、陈敏副教授、陈娅红副教授学术报告

信息来源: 暂无 发布日期: 2017-06-07 浏览次数:

报告人:王维凡教授,浙江师范大学

报告时间:  2017年6月10日9:00

报告地点:数计学院4号楼229室

报告题目:Edge-face  Coloring of Plane Graphs

报告人简介:王维凡,特聘教授,博士生导师,浙江师范大学校学术委员会副主任,基础数学省重点学科负责人,数学研究所执行所长,中国数学会理事,中国工业与应用数学学会理事,中国组合数学与图论学会理事,中国运筹学会图论组合专业委员会委员,浙江省数学会副理事长。主要从事图论及其应用的研究,发表论文200余篇。

报告摘要:The  edge-face chromatic number $\chi_{ef}(G)$ of a plane graph $G$ is the least  number of colors such that any two adjacent edges, adjacent faces, and incident  edge and face have different colors. In this talk we shall give a survey on the  edge-face coloring and list edge-face coloring of plane graphs. We also show  that every 2-connected and simple plane graph $G$ with maximum degree $\Delta\ge  16$ has $\chi_{ef}(G)=\Delta$.

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报告人:陈敏副教授,浙江师范大学

报告时间:  2017年6月10日10:00

报告地点:数计学院4号楼229室

报告题目:Choosability  with separation of planar graphs

报告摘要:A  $(k,d)$-list assignment $L$ of a graph $G$ is a function that assigns to each  vertex $v$ a list $L(v)$ of at least $k$ colors and $|L(x)\cap L(y)|\le d$ for  each edge $xy$. A graph $G$ is $(k,d)$-choosable if there exists an $L$-coloring  of $G$ for every $(k,d)$-list assignment $L$. This concept is known as  choosability with separation. In this talk, I firstly give a short survey on  this direction.Then, I will show that planar graphs with neither 5-cycles nor  chordal 6-cycles are $(3,1)$-choosable, which is a strengthening of a result in  [I. Choi, B. Lidick\'{y}, D. Stolee, On Choosability with separation of planar  graphs with forbidden cycles, J. Graph Theory, 2015] which says that planar  graphs with neither 5-cycles nor $6$-cycles are $(3,1)$-choosable. This is joint  work with Andr\'{e} Raspaud, Wai Chee Shiu and Weifan Wang.

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报告人:陈娅红副教授,丽水学院

报告时间:  2017年6月10日11:00

报告地点:数计学院4号楼229室

报告题目:Peripheral  Wiener index of trees and related questions

报告摘要:Distance-based  topological indices, as a class of graph invariants, have received much  attention. In particular, the Wiener index (sum of distances between all pairs  of vertices) and terminal Wiener index (sum of distances between all pairs of  leaves) are two of the most well known such indices in Chemical Graph Theory.  Inspired by these concepts, the peripheral Wiener index is recently introduced  as the sum of distances between all pairs of peripheral vertices (vertices with  maximum eccentricity). In this note we consider a number of interesting problems  related to this new distance-based index and propose some potential topics for  further study.