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A basic combinatorial invariant of a convex polytope $P$ is its $f$-vector $f(P)=(f_0,f_1,\dots,f_{\dim P-1})$, where $f_i$ is the number of $i$-dimensional faces of $P$. Steinitz characterized all possible $f$-vectors of $3$-polytopes and…

Combinatorics · Mathematics 2018-08-13 Takuya Kusunoki , Satoshi Murai

We introduce new families of combinatorial objects whose enumeration computes volumes of flow polytopes. These objects provide an interpretation, based on parking functions, of Baldoni and Vergne's generalization of a volume formula…

A permutation polytope is the convex hull of a group of permutation matrices. In this paper we investigate the combinatorics of permutation polytopes and their faces. As applications we completely classify permutation polytopes in…

Combinatorics · Mathematics 2010-02-14 Barbara Baumeister , Christian Haase , Benjamin Nill , Andreas Paffenholz

The convex hulls of face-vertex incident vectors of 3-face-colorable convex polytopes are computed. It is found that every such convex hull is a $d$-polytope with $d+2$ or $d+3$ vertices. Utilizing Gale transform and Gale diagram, we…

Combinatorics · Mathematics 2021-11-01 Bo Chen , Chen Peng , Yueshan Xiong

These lectures on the combinatorics and geometry of 0/1-polytopes are meant as an \emph{introduction} and \emph{invitation}. Rather than heading for an extensive survey on 0/1-polytopes I present some interesting aspects of these objects;…

Combinatorics · Mathematics 2007-05-23 Günter M. Ziegler

In order to understand the parameter space of monic and centered complex polynomial vector fields of degree d in the complex plane, decomposed by the combinatorial classes of the vector fields, it is interesting to know the number of loci…

Complex Variables · Mathematics 2011-10-18 Kealey Dias

Bisztriczky defines a multiplex as a generalization of a simplex, and an ordinary polytope as a generalization of a cyclic polytope. This paper presents results concerning the combinatorics of multiplexes and ordinary polytopes. The flag…

Combinatorics · Mathematics 2007-05-23 Margaret M. Bayer , Aaron M. Bruening , Joshua Stewart

We introduce the notion of a \emph{conic sequence} of a convex polytope. It is a way of building up a polytope starting from a vertex and attaching faces one by one with certain regulations. We apply this to a toric variety to obtain an…

Algebraic Topology · Mathematics 2021-06-09 Seonjeong Park , Jongbaek Song

We consider an interesting class of combinatorial symmetries of polytopes which we call \emph{edge-length preserving combinatorial symmetries}. These symmetries not only preserve the combinatorial structure of a polytope but also map each…

Metric Geometry · Mathematics 2020-11-24 Egor Morozov

Polytope numbers for a given polytope are an integer sequence defined by the combinatorics of the polytope. Recent work by H. K. Kim and J. Y. Lee has focused on writing polytope number sequences as sums of simplex number sequences. In…

Combinatorics · Mathematics 2015-07-08 Michael A. Jackson

The univariate Ehrhart and $h^*$-polynomials of lattice polytopes have been widely studied. We describe methods from toric geometry for computing multivariate versions of volume, Ehrhart and $h^*$-polynomials of lattice polytropes, which…

Combinatorics · Mathematics 2023-03-08 Marie-Charlotte Brandenburg , Sophia Elia , Leon Zhang

The degree partition of a simple graph is its degree sequence rearranged in weakly decreasing order. The polytope of degree partitions (respectively, degree sequences) is the convex hull of all degree partitions (respectively, degree…

Combinatorics · Mathematics 2007-05-23 Amitava Bhattacharya , S. Sivasubramanian , Murali K. Srinivasan

We call the $\delta$-vector of an integral convex polytope of dimension $d$ flat if the $\delta$-vector is of the form $(1,0,\ldots,0,a,\ldots,a,0,\ldots,0)$, where $a \geq 1$. In this paper, we give the complete characterization of…

Combinatorics · Mathematics 2020-09-08 Takayuki Hibi , Akiyoshi Tsuchiya

The Chan-Robbins-Yuen polytope can be thought of as the flow polytope of the complete graph with netflow vector $(1, 0, \ldots, 0, -1)$. The normalized volume of the Chan-Robbins-Yuen polytope equals the product of consecutive Catalan…

Combinatorics · Mathematics 2016-12-02 Sylvie Corteel , Jang Soo Kim , Karola Mészáros

In this work we study a class of random convex sets that "interpolate" between polytopes and zonotopes. These sets arise from considering a $q^{th}$-moment ($q\geq 1$) of an average of order statistics of $1$-dimensional marginals of a…

Metric Geometry · Mathematics 2017-01-06 David Alonso-Gutiérrez , Joscha Prochno

The matching polytope of a graph $G$ is the convex hull of the indicator vectors of the matchings on $G$. We characterize the graphs whose associated matching polytopes are Gorenstein, and then prove that all Gorenstein matching polytopes…

Combinatorics · Mathematics 2024-07-15 Benjamin Eisley , Koji Matsushita , Andrés R. Vindas-Meléndez

A graph is reconstructible if it is determined up to isomorphism by the multiset of its proper induced subgraphs. The reconstruction conjecture postulates that every graph of order at least 3 is reconstructible. We show that interval graphs…

Combinatorics · Mathematics 2026-05-13 Irene Heinrich , Masashi Kiyomi , Yota Otachi , Pascal Schweitzer

A transportation polytope consists of all multidimensional arrays or tables of non-negative real numbers that satisfy certain sum conditions on subsets of the entries. They arise naturally in optimization and statistics, and also have…

Combinatorics · Mathematics 2013-07-02 Jesús A. De Loera , Edward D. Kim

We investigate the intersection body of a convex polytope using tools from combinatorics and real algebraic geometry. In particular, we show that the intersection body of a polytope is always a semialgebraic set and provide an algorithm for…

Algebraic Geometry · Mathematics 2025-06-02 Katalin Berlow , Marie-Charlotte Brandenburg , Chiara Meroni , Isabelle Shankar

The $f$-vector of a polytope consists of the numbers of its $i$-dimensional faces. An open field of study is the characterization of all possible $f$-vectors. It has been solved in three dimensions by Steinitz in the early 19th century. We…

Metric Geometry · Mathematics 2020-02-21 Maren H. Ring , Robert Schüler
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