Séminaire Lotharingien de Combinatoire, 89B.7 (2023), 12 pp.

Yasuhide Numata, Yusuke Takahashi and Dai Tamaki

Faces of Directed Edge Polytopes

Abstract. Given a finite quiver (directed graph) without loops and multiedges, the convex hull of the column vector of the incidence matrix is called the directed edge polytope and is an interesting example of lattice polytopes. In this article, we give a complete characterization of facets of the directed edge polytope of an arbitrary finite quiver without loops and multiedges in terms of the connectivity and the existence of a rank function. Our result can be regarded as an extension of the result of Higashitani et al. on facets of symmetric edge polytopes to directed edge polytopes. When the quiver in question has a rank function, we obtain a characterization of faces of arbitrary dimensions. This article is an extended abstract of the full paper at arXiv:2203.14521.


Received: November 15, 2022. Accepted: February 20, 2023. Final version: April 1, 2023.

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