{ "id": "1607.08832", "version": "v1", "published": "2016-07-29T14:38:44.000Z", "updated": "2016-07-29T14:38:44.000Z", "title": "A note on the order of iterated line digraphs", "authors": [ "C. Dalfó", "M. A. Fiol" ], "categories": [ "math.CO" ], "abstract": "Given a digraph $G$, we propose a new method to find the recurrence equation for the number of vertices $n_k$ of the $k$-iterated line digraph $L^k(G)$, for $k\\geq0$, where $L^0(G)=G$. We obtain this result by using the minimal polynomial of a quotient digraph $\\pi(G)$ of $G$. We show some examples of this method applied to the so-called cyclic Kautz, the unicyclic, and the acyclic digraphs. In the first case, our method gives the enumeration of the ternary length-2 squarefree words of any length.", "revisions": [ { "version": "v1", "updated": "2016-07-29T14:38:44.000Z" } ], "analyses": { "subjects": [ "05C20", "05C50" ], "keywords": [ "iterated line digraph", "recurrence equation", "minimal polynomial", "quotient digraph", "cyclic kautz" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }