講座主題：Existence of non-Cayley Haar graphs
主講人： 楊大偉
工作單位：北京郵電大學
活動時間：2020年12月13日 14:50-15:40
講座地點：騰訊會議，會議ID：850 153 808
主辦單位：煙臺大學數學與信息科學學院
內容摘要：
A Cayley graph of a group H is a finite simple graphΓsuch that its automorphism group Aut(Γ) contains a subgroup isomorphic to H acting regularly on V(Γ), while a Haar graph of H is a finite simple bipartite graphΣsuch that Aut(Σ) contains a subgroup isomorphic to H acting semiregularly on V(Σ) and the H-orbits are equal to the partite sets ofΣ. It is well-known that every Haar graph of finite abelian groups is a Cayley graph. In this paper, we prove that every finite non-abelian group admits a non-Cayley Haar graph except the dihedral groups D6, D8, D10, the quaternion group Q8 and the group Q8×Z2. This answers an open problem proposed by Estelyi and Pisanski in 2016. This is joint work with Yan-Quan Feng, Istvan Kovacs and Jie Wang.
主講人介紹：
楊大偉，理學博士，北京郵電大學講師。研究方向為代數圖論、圖論與網絡，主要研究內容為圖與網絡的對稱性，網絡的嵌入與容錯性分析等。目前已在European J. Combin., J. Algebraic Combin., Inform. Sci.等國際期刊發表十余篇學術論文，主持或參與多項省部級以上科研項目。
