{ "id": "1609.00373", "version": "v1", "published": "2016-09-01T10:11:44.000Z", "updated": "2016-09-01T10:11:44.000Z", "title": "A study of the Structural Properties of finite $G$-graphs and their Characterisation", "authors": [ "Lord Clifford Kavi" ], "comment": "This is an MPhil thesis presented to the University of Ghana", "categories": [ "math.CO" ], "abstract": "The $G$-graph $\\Gamma(G,S)$ is a graph from the group $G$ generated by $S\\subseteq G$, where the vertices are the right cosets of the cyclic subgroups $\\langle s \\rangle, s\\in S$ with $k$-edges between two distinct cosets if there is an intersection of $k$ elements. In this thesis, after presenting some important properties of $G$-graphs, we show how the $G$-graph depends on the generating set of the group. We give the $G$-graphs of the symmetric group, alternating group and the semi-dihedral group with respect to various generating sets. We give a characterisation of finite $G$-graphs; in the general case and a bipartite case. Using these characterisations, we give several classes of graphs that are $G$-graphs. For instance, we consider the Tur\\'{a}n graphs, the platonic graphs and biregular graphs such as the Levi graphs of geometric configurations. We emphasis the structural properties of $G$-graphs and their relations to the group $G$ and the generating set $S$. As preliminary results for further studies, we give the adjacency matrix and spectrum of various finite $G$-graphs. As an application, we compute the energy of these graphs. We also present some preliminary results on infinite $G$-graphs where we consider the $G$-graphs of the infinite group $SL_2(\\mathbb{Z})$ and an infinite non-Abelian matrix group.", "revisions": [ { "version": "v1", "updated": "2016-09-01T10:11:44.000Z" } ], "analyses": { "subjects": [ "05C25", "05C50" ], "keywords": [ "structural properties", "characterisation", "generating set", "preliminary results", "infinite non-abelian matrix group" ], "tags": [ "dissertation" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }