{ "id": "2012.12705", "version": "v1", "published": "2020-12-23T14:32:35.000Z", "updated": "2020-12-23T14:32:35.000Z", "title": "On distance matrices of helm graphs obtained from wheel graphs with an even number of vertices", "authors": [ "Shivani Goel" ], "categories": [ "math.CO", "math.FA" ], "abstract": "Let $n \\geq 4$. The helm graph $H_n$ on $2n-1$ vertices is obtained from the wheel graph $W_n$ by adjoining a pendant edge to each vertex of the outer cycle of $W_n$. Suppose $n$ is even. Let $D := [d_{ij}]$ be the distance matrix of $H_n$. In this paper, we first show that $\\det(D) = 3(n-1)2^{n-1}.$ Next, we find a matrix $\\L$ and a vector $u$ such that \\[D^{-1} = -\\frac{1}{2}\\L+\\frac{4}{3(n-1)}uu'.\\] We also prove an interlacing property between the eigenvalues of $\\L$ and $D$.", "revisions": [ { "version": "v1", "updated": "2020-12-23T14:32:35.000Z" } ], "analyses": { "subjects": [ "05C50" ], "keywords": [ "distance matrix", "helm graph", "wheel graph", "outer cycle", "pendant edge" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }