{ "id": "1611.03221", "version": "v1", "published": "2016-11-10T08:54:40.000Z", "updated": "2016-11-10T08:54:40.000Z", "title": "Indecomposable $1$-factorizations of the complete multigraph $λ K_{2n}$ for every $λ\\leq 2n$", "authors": [ "Simona Bonvicini", "Gloria Rinaldi" ], "categories": [ "math.CO" ], "abstract": "A $1$-factorization of the complete multigraph $\\lambda K_{2n}$ is said to be indecomposable if it cannot be represented as the union of $1$-factorizations of $\\lambda_0 K_{2n}$ and $(\\lambda-\\lambda_0) K_{2n}$, where $\\lambda_0<\\lambda$. It is said to be simple if no $1$-factor is repeated. For every $n\\geq 9$ and for every $(n-2)/3\\leq\\lambda\\leq 2n$, we construct an indecomposable $1$-factorization of $\\lambda K_{2n}$ which is not simple. These $1$-factorizations provide simple and indecomposable $1$-factorizations of $\\lambda K_{2s}$ for every $s\\geq 18$ and $2\\leq\\lambda\\leq 2\\lfloor s/2\\rfloor-1$. We also give a generalization of a result by Colbourn et al. which provides a simple and indecomposable $1$-factorization of $\\lambda K_{2n}$, where $2n=p^m+1$, $\\lambda=(p^m-1)/2$, $p$ prime.", "revisions": [ { "version": "v1", "updated": "2016-11-10T08:54:40.000Z" } ], "analyses": { "subjects": [ "05C70" ], "keywords": [ "complete multigraph", "factorization", "indecomposable" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }