应数学与统计学院徐守军教授邀请，南开大学史永堂教授将于2019年01月13-14日访问我校并作学术报告。

报 告：Some extremal results for planar graphs

时 间：2019年1月13日下午15:00

地 点：齐云楼911报告厅

欢迎广大师生参加！

摘要：Motivated by anti-Ramsey numbers introduced by Erdős, Simonovits and Sós in1975, we study the anti-Ramsey problem when host graphs are plane triangulations. Given a positive integer n and a plane graphH, let T_n(H) be the family of all plane triangulationsT on n vertices such that T contains H as a subgraph. The planar anti-Ramsey number of H, denoted ar_P(n, H), is the maximum number k such that no edge-coloring of any plane triangulation in T_n(H) with k colors contains a rainbow copy of H. The study of ar_P(n, H)(under the name of rainbow numbers) was initiated by Horňák, Jendrol', Schiermeyer and Soták [J Graph Theory 78 (2015) 248-257].

Turán-type problems was initiated by Mantel (1907) and Turán (1941), which was generalized soon by Erdős et al. Dirac (1964) and Mader (1967) started to investigate extremal problems for K_t-minor-free graphs. The planar Turán number of F, denoted ex_P(n, F), is the maximum number of edges of any F-free planar graph on n vertices, which was first studied by Dowden [J. Graph Theory 83(2016) 213-230].

In this talk, we will present some extremal results for planar graphs, especially, some results on planar anti-Ramsey numbers and planar Turán numbers.

报告人简介

史永堂，南开大学教授，博士生导师。2009年6月获南开大学理学博士学位，2014-2015年加拿大西门菲沙大学访问学者，曾受邀到美国、德国、奥地利等国访问交流。主要从事图论与组合优化方面的教学与研究工作，发表学术论文50余篇，出版专著1部（Springer出版社），编著3部（Wiley、CRC），译著2部（高等教育出版社）。主持多项国家自然科学基金和天津市自然科学基金项目，入选天津市人才特支计划“青年拔尖人才”、南开大学“百名青年学科带头人培养计划”等。担任天津市工业与应用数学学会秘书长，中国运筹学会图论组合分会青年理事，中国工业与应用数学学会组织委员会委员、图论组合及其应用专委会委员、复杂网络与复杂系统专委会委员等。

应用数学与复杂系统省级重点实验室

数学与统计学院

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2019年01月07日