{ "id": "2109.13849", "version": "v2", "published": "2021-09-28T16:26:17.000Z", "updated": "2022-03-28T19:02:11.000Z", "title": "On bipartite distance-regular Cayley graphs with small diameter", "authors": [ "Edwin R. van Dam", "Mojtaba Jazaeri" ], "comment": "21 pages", "categories": [ "math.CO" ], "abstract": "We study bipartite distance-regular Cayley graphs with diameter three or four. We give sufficient conditions under which a bipartite Cayley graph can be constructed on the semidirect product of a group -- the part of this bipartite Cayley graph which contains the identity element -- and $\\mathbb{Z}_{2}$. We apply this to the case of bipartite distance-regular Cayley graphs with diameter three, and consider cases where the sufficient conditions are not satisfied for some specific groups such as the dihedral group. We also extend a result by Miklavi\\v{c} and Poto\\v{c}nik that relates difference sets to bipartite distance-regular Cayley graphs with diameter three to the case of diameter four. This new case involves certain partial geometric difference sets and -- in the antipodal case -- relative difference sets.", "revisions": [ { "version": "v2", "updated": "2022-03-28T19:02:11.000Z" } ], "analyses": { "keywords": [ "small diameter", "bipartite cayley graph", "study bipartite distance-regular cayley graphs", "sufficient conditions", "partial geometric difference sets" ], "note": { "typesetting": "TeX", "pages": 21, "language": "en", "license": "arXiv", "status": "editable" } } }