{ "id": "1809.07718", "version": "v1", "published": "2018-09-20T16:13:15.000Z", "updated": "2018-09-20T16:13:15.000Z", "title": "On the largest $A_α$-spectral radius of cacti", "authors": [ "Shaohui Wang", "Chunxiang Wang", "Jia-Bao Liu", "Bing Wei" ], "comment": "submitted", "categories": [ "math.CO" ], "abstract": "Let $A(G)$ be the adjacent matrix and $D(G)$ the diagonal matrix of the degrees of a graph $G$, respectively. For $0 \\leq \\alpha \\leq 1$, the $A_{\\alpha}$ matrix $A_{\\alpha}(G) = \\alpha D(G) +(1-\\alpha)A(G)$ is given by Nikiforov. Clearly, $A_{0} (G)$ is the adjacent matrix and $2 A_{\\frac{1}{2}}$ is the signless Laplacian matrix. A cactus is a connected graph such that any two of its cycles have at most one common vertex, that is an extension of the tree. The $A_{\\alpha}$-spectral radius of a cactus graph with $n$ vertices and $k$ cycles is explored. The outcomes obtained in this paper can imply previous bounds of Nikiforov et al., and Lov\\'{a}sz and Pelik\\'{a}n. In addition, the corresponding extremal graphs are determined. Furthermore, we proposed all eigenvalues of such extremal cacti. Our results extended and enriched previous known results.", "revisions": [ { "version": "v1", "updated": "2018-09-20T16:13:15.000Z" } ], "analyses": { "keywords": [ "spectral radius", "adjacent matrix", "diagonal matrix", "signless laplacian matrix", "corresponding extremal graphs" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }