{ "id": "2301.07467", "version": "v1", "published": "2023-01-18T12:21:24.000Z", "updated": "2023-01-18T12:21:24.000Z", "title": "Many Hamiltonian subsets in large graphs with given density", "authors": [ "Stijn Cambie", "Jun Gao", "Hong Liu" ], "comment": "11 pages", "categories": [ "math.CO" ], "abstract": "A set of vertices in a graph is a Hamiltonian subset if it induces a subgraph containing a Hamiltonian cycle. Kim, Liu, Sharifzadeh and Staden proved that among all graphs with minimum degree $d$, $K_{d+1}$ minimises the number of Hamiltonian subsets. We prove a near optimal lower bound that takes also the order and the structure of a graph into account. For many natural graph classes, it provides a much better bound than the extremal one ($\\approx 2^{d+1}$). Among others, our bound implies that an $n$-vertex $C_4$-free graphs with minimum degree $d$ contains at least $n2^{d^{2-o(1)}}$ Hamiltonian subsets.", "revisions": [ { "version": "v1", "updated": "2023-01-18T12:21:24.000Z" } ], "analyses": { "subjects": [ "05C35", "05C38", "05C48" ], "keywords": [ "hamiltonian subset", "large graphs", "minimum degree", "natural graph classes", "optimal lower bound" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }