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【预告】钱建国教授学术报告

来源: 日期:2020-11-02 作者: 浏览次数:

报告题目Inclusion-exclusion cancellation and application to graph polynomials

报告时间:2020年11月3日下午15:00

报告地点:科学会堂A710报告厅

人:

钱建国,厦门大学数学科学学院教授,博士生导师,主要从事图论应用(化学图论、网络拓扑结构设计与优化)及组合计数方面的研究。现任中国组合数学与图论专业委员会委员,中国运筹学会图论分会常务理事,福建省运筹学会副理事长。美国数学会《数学评论》评论员,发表评论40余篇;主持和参加多项国家面上及重点基金项目; 在包括J. Combin. Theory(Ser A, Ser B)及J. Graph Theory等在内的国内外专业期刊上发表学术论文60余篇。

报告摘要

Whitney's broken cycle theorem gives a very nice `cancellation' to reduce some terms in the chromatic polynomial (represented in the form of inclusion-exclusion) such that the remaining terms cannot be cancellated out anymore and therefore, yield a combinatorial interpretation for the coefficients of the chromatic polynomial. So far, the known cancellations for the inclusion-exclusion formula strongly depend on the prescribed (linear or partial) ordering on the index set. We give a new cancellation method, which does not require any ordering on the index set. Our method extends all the“ordering-based”methods known in the literature and in general reduces more terms. As examples, we apply our method to some classic graph polynomials.