{ "id": "2006.03289", "version": "v1", "published": "2020-06-05T08:17:45.000Z", "updated": "2020-06-05T08:17:45.000Z", "title": "On distance matrices of wheel graphs with odd number of vertices", "authors": [ "R. Balaji", "R. B. Bapat", "Shivani Goel" ], "categories": [ "math.CO", "math.FA" ], "abstract": "Let $W_n$ denote the wheel graph having $n$-vertices. If $i$ and $j$ are any two vertices of $W_n$, define \\[d_{ij}:= \\begin{cases} 0 & \\mbox{if}~i=j \\\\ 1 & \\mbox{if}~i~ \\mbox{and} ~j~ \\mbox{are adjacent} \\\\ 2 & \\mbox{else}. \\end{cases}\\] Let $D$ be the $n \\times n$ matrix with $(i,j)^{\\rm th}$ entry equal to $d_{ij}$. The matrix $D$ is called the distance matrix of $W_n$. Suppose $n \\geq 5$ is an odd integer. In this paper, we deduce a formula to compute the Moore-Penrose inverse of $D$. More precisely, we obtain an $n\\times n$ matrix $\\widetilde{L}$ and a rank one matrix $ww'$ such that \\[D^\\dagger = -\\frac{1}{2} \\widetilde{L}+\\frac{4}{n-1}ww'.\\] Here, $\\widetilde{L}$ is positive semidefinite, ${\\rm rank}(\\widetilde{L})=n-2$ and all row sums are equal to zero.", "revisions": [ { "version": "v1", "updated": "2020-06-05T08:17:45.000Z" } ], "analyses": { "subjects": [ "05C50" ], "keywords": [ "distance matrix", "wheel graph", "odd number", "entry equal", "odd integer" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }