一、题目:
Connectivity of contraction-critical graphs
二、主讲人:
喻革新
三、摘要:
Contraction-critical graphs comes from the study of minimal counterexamples to Hadwiger's conjecture. A graph is k-contraction-critical if it is k-chromatic, but any proper minor is (k-1)-colorable. It is a long-standing result of Mader that k-contraction-critical graphs are 7-connected for k at least 7. In this paper, we provide the improvement of Mader's result for small values of k. We show that k-contraction-critical graphs are 8-connected for k at least 17, 9-connected for k at least 29 and 10-connected for k at least 49. As a corollary of one of our intermediate results, we also prove that every 30-connected graph is 4-linked. This is based on joint work with Runrun Liu and Martin Rolek.
四、主讲人简介:
喻革新,美国威廉玛丽学院(College of William and Mary)教授。2006年毕业于伊利诺伊大学香槟分校(UIUC)获博士学位。2006-2008年在范德堡大学(Vanderbilt)做博士后研究。主要研究方向为图论,组合及其应用。主持完成多项美国NSF项目和NSA基金,并主持组织国际学术会议十余次,多次在国际学术会议做邀请报告。在图染色,图链接,图嵌入等方向发表被SCI收录学术论文80余篇,其中在图论组合顶级期刊发表论文多篇,如J. Combin. Theory, Ser. B,Combinatorica,SIAM J. on Discrete Mathematics等。
五、邀请人:
王光辉 数学学院教授
六、时间:
12月27日(周一)10:00
七、地点:
Zoom会议,会议ID:821 6105 8724,密码:202121
八、主办方:
山东大学数学学院