{ "id": "1709.00706", "version": "v1", "published": "2017-09-03T12:01:10.000Z", "updated": "2017-09-03T12:01:10.000Z", "title": "The Automorphism Group of the Reduced Complete-Empty $X-$Join of Graphs", "authors": [ "Adel Tadayyonfar", "Ali Reza Ashrafi" ], "comment": "19 pages, 0 figure", "categories": [ "math.GR" ], "abstract": "Suppose $X$ is a simple graph. The $X-$join $\\Gamma$ of a set of complete or empty graphs $\\{X_x \\}_{x \\in V(X)}$ is a simple graph with the following vertex and edge sets: \\begin{eqnarray*} V(\\Gamma) &=& \\{(x,y) \\ | \\ x \\in V(X) \\ \\& \\ y \\in V(X_x) \\},\\\\ E(\\Gamma) &=& \\{(x,y)(x^\\prime,y^\\prime) \\ | \\ xx^\\prime \\in E(X) \\ or \\ else \\ x = x^\\prime \\ \\& \\ yy^\\prime \\in E(X_x)\\}. \\end{eqnarray*} The $X-$join graph $\\Gamma$ is called reduced if for vertices $x, y \\in V(X)$, $x \\ne y$, $N_X(x) \\setminus \\{ y\\} = N_X(y) \\setminus \\{ x\\}$ implies that $(i)$ if $xy \\not\\in E(X)$ then the graphs $X_x$ or $X_y$ are non-empty; $(ii)$ if $xy \\in E(X)$ then $X_x$ or $X_y$ are not complete graphs. In this paper, we want to explore how the graph theoretical properties of $X-$join of graphs effect on its automorphism group. Among other results we compute the automorphism group of reduced complete-empty $X-$join of graphs.", "revisions": [ { "version": "v1", "updated": "2017-09-03T12:01:10.000Z" } ], "analyses": { "subjects": [ "20B25", "05C50" ], "keywords": [ "automorphism group", "reduced complete-empty", "simple graph", "graphs effect", "graph theoretical properties" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }