{ "id": "1907.02635", "version": "v1", "published": "2019-07-04T03:03:47.000Z", "updated": "2019-07-04T03:03:47.000Z", "title": "The number of rooted forests in circulant graphs", "authors": [ "L. A. Grunwald", "I. A. Mednykh" ], "comment": "14 pages. arXiv admin note: substantial text overlap with arXiv:1711.00175, arXiv:1812.04484", "categories": [ "math.CO" ], "abstract": "In this paper, we develop a new method to produce explicit formulas for the number $f_{G}(n)$ of rooted spanning forests in the circulant graphs $ G=C_{n}(s_1,s_2,\\ldots,s_k)$ and $ G=C_{2n}(s_1,s_2,\\ldots,s_k,n).$ These formulas are expressed through Chebyshev polynomials. We prove that in both cases the number of rooted spanning forests can be represented in the form $f_{G}(n)=p\\,a(n)^2,$ where $a(n)$ is an integer sequence and $p$ is a prescribed natural number depending on the parity of $n$. Finally, we find an asymptotic formula for $f_{G}(n)$ through the Mahler measure of the associated Laurent polynomial $P(z)=2k+1-\\sum\\limits_{i=1}^k(z^{s_i}+z^{-s_i}).$", "revisions": [ { "version": "v1", "updated": "2019-07-04T03:03:47.000Z" } ], "analyses": { "subjects": [ "05C30", "39A12" ], "keywords": [ "circulant graphs", "rooted forests", "rooted spanning forests", "produce explicit formulas", "asymptotic formula" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }