{ "id": "2007.00115", "version": "v1", "published": "2020-06-30T21:23:11.000Z", "updated": "2020-06-30T21:23:11.000Z", "title": "Hamiltonicity of the Double Vertex Graph and the Complete Double Vertex Graph of some Join Graphs", "authors": [ "Luis Adame", "Luis Manuel Rivera", "Ana Laura Trujillo-Negrete" ], "categories": [ "math.CO" ], "abstract": "Let $G$ be a simple graph of order $n$. The double vertex graph $F_2(G)$ of $G$ is the graph whose vertices are the $2$-subsets of $V(G)$, where two vertices are adjacent in $F_2(G)$ if their symmetric difference is a pair of adjacent vertices in $G$. A generalization of this graph is the complete double vertex graph $M_2(G)$ of $G$, defined as the graph whose vertices are the $2$-multisubsets of $V(G)$, and two of such vertices are adjacent in $M_2(G)$ if their symmetric difference (as multisets) is a pair of adjacent vertices in $G$. In this paper we exhibit an infinite family of graphs (containing Hamiltonian and non-Hamiltonian graphs) for which $F_2(G)$ and $M_2(G)$ are Hamiltonian. This family of graphs is the set of join graphs $G=G_1 + G_2$, where $G_1$ and $G_2$ are of order $m\\geq 1$ and $n\\geq 2$, respectively, and $G_2$ has a Hamiltonian path. For this family of graphs, we show that if $m\\leq 2n$ then $F_2(G)$ is Hamiltonian, and if $m\\leq 2(n-1)$ then $M_2(G)$ is Hamiltonian.", "revisions": [ { "version": "v1", "updated": "2020-06-30T21:23:11.000Z" } ], "analyses": { "subjects": [ "05C45", "05C76" ], "keywords": [ "complete double vertex graph", "join graphs", "symmetric difference", "adjacent vertices", "hamiltonicity" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }