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.
