报告人:董峰明（新加坡南洋理工大学）

日  期: 2019年7月12日

时  间: 上午10:00

地  点: 理科楼 LD202

摘  要: The four-color conjecture (i.e., every map can be colored by at most four colors such that adjacent counties  receive different colors) was proposed by Francis Guthrie from England in 1852. This conjecture was first proved by Kenneth Appel and Wolfgang Haken from the University of Illinois in 1976. They constructed a computer-assisted proof for this conjecture.

However, because part of the proof consisted of an exhaustive analysis of many discrete cases by a computer, some mathematicians do not accept it.

In 1997, Neil Robertson, Daniel P. Sanders, Paul Seymour and  Robin Thomas found a similar but more efficient proof because it reduced the complexity of the problem and required checking only 633 reducible configurations when compared to the 1476 reducible configurations in Appel and Haken's proof.

Although the conjecture is considered proven, more than a century of investigation of the four-color conjecture (by several famous mathematicians, using various methods and approaches) has resulted in many fruitful studies of new problems. In this talk I will introduce some lines of research which were triggered by the study of the four-color conjecture.

报告人简介：董峰明，现为新加坡南洋理工大学副教授、博士生导师。1997年毕业于新加坡国立大学，获得博士学位；2008年，受邀访问英国剑桥大学牛顿数学科学研究所。主要研究兴趣为图论与拟阵论，特别是图和拟阵的结构与多项式的关系。出版专著《Chromatic polynomials and chromaticity of graphs》,已发表论文近80篇（JCTA、JCTB等），解决了若干公开问题及猜想，包括Bartels和Welsh提出的“Shameful Conjecture”,是图的色多项式领域的著名专家。

学院联系人:傅士硕

欢迎广大师生积极参与！