{ "id": "2211.08105", "version": "v1", "published": "2022-11-15T12:51:17.000Z", "updated": "2022-11-15T12:51:17.000Z", "title": "Few hamiltonian cycles in graphs with one or two vertex degrees", "authors": [ "Jan Goedgebeur", "Jorik Jooken", "On-Hei Solomon Lo", "Ben Seamone", "Carol T. Zamfirescu" ], "categories": [ "math.CO", "cs.DM" ], "abstract": "We fully disprove a conjecture of Haythorpe on the minimum number of hamiltonian cycles in regular hamiltonian graphs, thereby extending a result of Zamfirescu, as well as correct and complement Haythorpe's computational enumerative results from [Experim. Math. 27 (2018) 426-430]. Thereafter, we use the Lov\\'asz Local Lemma to extend Thomassen's independent dominating set method. Regarding the limitations of this method, we answer a question of Haxell, Seamone, and Verstraete, and settle the first open case of a problem of Thomassen. Motivated by an observation of Aldred and Thomassen, we prove that for every $\\kappa \\in \\{ 2, 3 \\}$ and any positive integer $k$, there are infinitely many non-regular graphs of connectivity $\\kappa$ containing exactly one hamiltonian cycle and in which every vertex has degree $3$ or $2k$.", "revisions": [ { "version": "v1", "updated": "2022-11-15T12:51:17.000Z" } ], "analyses": { "keywords": [ "hamiltonian cycle", "vertex degrees", "thomassens independent dominating set method", "complement haythorpes computational enumerative results", "extend thomassens independent dominating set" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }