报告题目：Colorings v.s. list colorings of graph and hypergraph

摘要：For a graph G, Donner in 1992 showed that the list coloring function P_l(G,k) equals the chromatic polynomial P(G,k) when k is sufficiently large (compared to the number of vertices). Later in 2009, Thomassen specified the `sufficiently large k' by `k> |V|^{10}'. Recently, we improve the latter result to k>\frac{m-1}{\ln(1+\sqrt{2})} and generalize further to r-uniform hypergraphs for any r\ge 2:

\noindent{\bf Theorem} For any connected $r$-uniform hypergraph G with m edges and r\geq 2, if

k>\frac{m-1}{\ln(1+\sqrt{2})}\approx 1.135 (m-1)

then P_l(G, k) = P(G, k) and the k-list assignment admitting the fewest colorings is the constant k-list assignment.

报告时间：2018年5月29号下午3：30--4：30

报告地点：002cc白菜资讯三楼专家接待室

报告人简介：钱建国，厦门大学教授，美国数学会《数学评论》评论员，中国数学会组合数学与图论学会理事，福建数学会理事，福建省组合数学与图论学会常务理事。于1998年获得四川大学理学博士学位，先后到德国Bielefeld大学和台湾大学进行学术交流和访问，2000年以来参加国家重点项目一项并主持和参加多项国家与省自然科学基金项目。