报告题目： Regular Permutation Sets

报告时间: 2018年10月9日16点00分-17点00分

报告地点: 数学院大会议室

报告人: Professor Robert Jajcay （Comenius University）

报告人简介：Robert Jajcay，斯洛伐克考门斯基大学(Comenius University)数学与计算机学院教授。 1995年在 University of Nebraska-Lincoln获数学博士学位，是国际著名的图论学者，曾经是美国印第安纳州立大学教授。

内容摘要： The concept of a -transitive group of permutations is well-known and widely studied. We propose the study of an analogous concept of a -regular set of permutations, i.e., set of permutations acting on a base set and having the regularity property that for each pair of elements , exactly permutations from map to . Not requiring the set to form a group makes it hard to use concepts traditionally used in group theory, and requires developing different tools and approaches.

In our talk, we present some basic properties of -regular sets of permutations, and then apply the newly developed tools to -regular sets of graph automorphisms. We exhibit

graphs admitting -regular sets of automorphisms for arbitrary large , mostly relying on merged Johnson graphs and Praeger-Xu graphs.