{ "id": "1710.00252", "version": "v1", "published": "2017-09-30T19:35:06.000Z", "updated": "2017-09-30T19:35:06.000Z", "title": "Laplacian Simplices Associated to Digraphs", "authors": [ "Gabriele Balletti", "Takayuki Hibi", "Marie Meyer", "Akiyoshi Tsuchiya" ], "categories": [ "math.CO" ], "abstract": "We associate to a finite digraph $D$ a lattice polytope $P_D$ whose vertices are the rows of the Laplacian matrix of $D$. This generalizes a construction introduced by Braun and the third author. As a consequence of the Matrix-Tree Theorem, we show that the normalized volume of $P_D$ equals the complexity of $D$, and $P_D$ contains the origin in its relative interior if and only if $D$ is strongly connected. Interesting connections with other families of simplices are established and then used to describe reflexivity, $h^*$-polynomial, and integer decomposition property of $P_D$ in these cases. We extend Braun and Meyer's study of cycles by considering cycle digraphs. In this setting we characterize reflexivity and show there are only four non-trivial reflexive Laplacian simplices having the integer decomposition property.", "revisions": [ { "version": "v1", "updated": "2017-09-30T19:35:06.000Z" } ], "analyses": { "subjects": [ "52B20", "05C20" ], "keywords": [ "integer decomposition property", "non-trivial reflexive laplacian simplices", "lattice polytope", "considering cycle digraphs", "meyers study" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }