The Face Structure and Geometry of Marked Order Polyhedra
- 36 Downloads
We study a class of polyhedra associated to marked posets. Examples of these polyhedra are Gelfand–Tsetlin polytopes and cones, as well as Berenstein–Zelevinsky polytopes—all of which have appeared in the representation theory of semi-simple Lie algebras. The faces of these polyhedra correspond to certain partitions of the underlying poset and we give a combinatorial characterization of these partitions. We specify a class of marked posets that give rise to polyhedra with facets in correspondence to the covering relations of the poset. On the convex geometrical side, we describe the recession cone of the polyhedra, discuss products and give a Minkowski sum decomposition. We briefly discuss intersections with affine subspaces that have also appeared in representation theory and recently in the theory of finite Hilbert space frames.
KeywordsMarked poset polytopes Gelfand–Tsetlin polytopes Polyhedral geometry Representation theory
Unable to display preview. Download preview PDF.
- 2.An, B.H., Cho, Y., Kim, J.S.: On the f-vectors of Gelfand–Cetlin polytopes. ArXiv e-prints. (2016). arXiv:1606.05957
- 8.Geissinger, L.: The face structure of a poset polytope. In: Proceedings of the Third Caribbean conference in combinatorics and computing, pp. 125–133 (1981)Google Scholar
- 13.Hibi, T., Li, N., Sahara, Y., Shikama, A.: The numbers of edges of the order polytope and the chain poyltope of a finite partially ordered set. ArXiv e-prints. (2015). arXiv:1508.00187