{ "id": "2406.03561", "version": "v1", "published": "2024-06-05T18:17:29.000Z", "updated": "2024-06-05T18:17:29.000Z", "title": "Energy of a graph and Randić index of subgraphs", "authors": [ "Gerardo Arizmendi", "Diego Huerta" ], "comment": "12 pages, 3 figures", "categories": [ "math.CO" ], "abstract": "We give a new inequality between the energy of a graph and a weighted sum over the edges of the graph. Using this inequality we prove that $\\mathcal{E}(G)\\geq 2R(H)$, where $ \\mathcal{E}(G)$ is the energy of a graph $G$ and $R(H)$ is the Randi\\'c index of any subgraph of $G$ (not necessarily induced). In particular, this generalizes well-known inequalities $\\mathcal{E}(G)\\geq 2R(G)$ and $\\mathcal{E}(G)\\geq 2\\mu(G)$ where $\\mu(G)$ is the matching number. We give other inequalities as applications to this result.", "revisions": [ { "version": "v1", "updated": "2024-06-05T18:17:29.000Z" } ], "analyses": { "subjects": [ "05C50", "05C09" ], "keywords": [ "inequality", "generalizes well-known inequalities", "randic index", "weighted sum" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }