{ "id": "2312.16447", "version": "v1", "published": "2023-12-27T07:24:27.000Z", "updated": "2023-12-27T07:24:27.000Z", "title": "On the complexity of Cayley graphs on a dihedral group", "authors": [ "Bobo Hua", "Alexander Mednykh", "Ilya Mednykh", "Lili Wang" ], "categories": [ "math.CO" ], "abstract": "In this paper, we investigate the complexity of an infinite family of Cayley graphs $\\mathcal{D}_{n}=Cay(\\mathbb{D}_{n}, b^{\\pm\\beta_1},b^{\\pm\\beta_2},\\ldots,b^{\\pm\\beta_s}, a b^{\\gamma_1}, a b^{\\gamma_2},\\ldots, a b^{\\gamma_t} )$ on the dihedral group $\\mathbb{D}_{n}=\\langle a,b| a^2=1, b^n=1,(a\\,b)^2=1\\rangle$ of order $2n.$ We obtain a closed formula for the number $\\tau(n)$ of spanning trees in $\\mathcal{D}_{n}$ in terms of Chebyshev polynomials, investigate some arithmetical properties of this function, and find its asymptotics as $n\\to\\infty.$ Moreover, we show that the generating function $F(x)=\\sum\\limits_{n=1}^\\infty\\tau(n)x^n$ is a rational function with integer coefficients.", "revisions": [ { "version": "v1", "updated": "2023-12-27T07:24:27.000Z" } ], "analyses": { "subjects": [ "05C30", "39A12" ], "keywords": [ "dihedral group", "cayley graphs", "complexity", "chebyshev polynomials", "rational function" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }