{ "id": "2003.06624", "version": "v1", "published": "2020-03-14T13:11:47.000Z", "updated": "2020-03-14T13:11:47.000Z", "title": "On $\\BCI$-groups and $\\CI$-groups", "authors": [ "Asieh Sattari", "Majid Arezoomand", "Mohammad A. Iranmanesh" ], "comment": "12 pages", "categories": [ "math.GR" ], "abstract": "Let $G$ be a finite group and $S$ be a subset of $G.$ A bi-Cayley graph $\\BCay(G,S)$ is a simple and an undirected graph with vertex-set $G\\times\\{1,2\\}$ and edge-set $\\{\\{(g,1),(sg,2)\\}\\mid g\\in G, s\\in S\\}$. A bi-Cayley graph $\\BCay(G,S)$ is called a $\\BCI$-graph if for any bi-Cayley graph $\\BCay(G,T)$, whenever $\\BCay(G,S)\\cong\\BCay(G,T)$ we have $T=gS^\\sigma$ for some $g\\in G$ and $\\sigma\\in\\Aut(G).$ A group $G$ is called a $\\BCI$-group if every bi-Cayley graph of $G$ is a $\\BCI$-graph. In this paper, we showed that every $\\BCI$-group is a $\\CI$-group, which gives a positive answer to a conjecture proposed by Arezoomand and Taeri in \\cite{arezoomand1}. Also we proved that there is no any non-Abelian $4$-$\\BCI$-simple group. In addition all $\\BCI$-groups of order $2p$, $p$ a prime, are characterized.", "revisions": [ { "version": "v1", "updated": "2020-03-14T13:11:47.000Z" } ], "analyses": { "keywords": [ "bi-cayley graph", "finite group", "simple group", "undirected graph", "vertex-set" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }