{ "id": "1301.1794", "version": "v1", "published": "2013-01-09T09:48:48.000Z", "updated": "2013-01-09T09:48:48.000Z", "title": "A construction for infinite families of semisymmetric graphs revealing their full automorphism group", "authors": [ "Philippe Cara", "Sara Rottey", "Geertrui Van de Voorde" ], "categories": [ "math.CO" ], "abstract": "We give a general construction leading to different non-isomorphic families $\\Gamma_{n,q}(\\K)$ of connected $q$-regular semisymmetric graphs of order $2q^{n+1}$ embedded in $\\PG(n+1,q)$, for a prime power $q=p^h$, using the linear representation of a particular point set $\\K$ of size $q$ contained in a hyperplane of $\\PG(n+1,q)$. We show that, when $\\K$ is a normal rational curve with one point removed, the graphs $\\Gamma_{n,q}(\\K)$ are isomorphic to the graphs constructed for $q$ prime in [9] and to the graphs constructed for $q=p^h$ in [20]. These graphs were known to be semisymmetric but their full automorphism group was up to now unknown. For $q\\geq n+3$ or $q=p=n+2$, $n\\geq 2$, we obtain their full automorphism group from our construction by showing that, for an arc $\\K$, every automorphism of $\\Gamma_{n,q}(\\K)$ is induced by a collineation of the ambient space $\\PG(n+1,q)$. We also give some other examples of semisymmetric graphs $\\Gamma_{n,q}(\\K)$ for which not every automorphism is induced by a collineation of their ambient space.", "revisions": [ { "version": "v1", "updated": "2013-01-09T09:48:48.000Z" } ], "analyses": { "subjects": [ "51E20", "20B25" ], "keywords": [ "full automorphism group", "semisymmetric graphs revealing", "infinite families", "construction", "ambient space" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1301.1794C" } } }