Inside-out polytopes

M Beck, T Zaslavsky - Advances in Mathematics, 2006 - Elsevier
We present a common generalization of counting lattice points in rational polytopes and the
enumeration of proper graph colorings, nowhere-zero flows on graphs, magic squares and …

Many faces of symmetric edge polytopes

A D'Alì, E Delucchi, M Michałek - arXiv preprint arXiv:1910.05193, 2019 - arxiv.org
Symmetric edge polytopes are a class of lattice polytopes constructed from finite simple
graphs. In the present paper we highlight their connections to the Kuramoto synchronization …

On a generalization of symmetric edge polytopes to regular matroids

A D'Alì, M Juhnke-Kubitzke… - International Mathematics …, 2024 - academic.oup.com
Starting from any finite simple graph, one can build a reflexive polytope known as a
symmetric edge polytope. The first goal of this paper is to show that symmetric edge …

Multiple weak 2-linkage and its applications on integer flows of signed graphs

Y Lu, R Luo, CQ Zhang - European Journal of Combinatorics, 2018 - Elsevier
For two pairs of vertices x 1, y 1 and x 2, y 2, Seymour and Thomassen independently
presented a characterization of graphs containing no edge-disjoint (x 1, y 1)-path and (x 2, y …

Ehrhart theory, modular flow reciprocity, and the Tutte polynomial

F Breuer, R Sanyal - Mathematische Zeitschrift, 2012 - Springer
Given an oriented graph G, the modular flow polynomial\phi_G (k) counts the number of
nowhere-zero Z _k-flows of G. We give a description of the modular flow polynomial in terms …

[HTML][HTML] Enumerating colorings, tensions and flows in cell complexes

M Beck, F Breuer, L Godkin, JL Martin - Journal of Combinatorial Theory …, 2014 - Elsevier
We study quasipolynomials enumerating proper colorings, nowhere-zero tensions, and
nowhere-zero flows in an arbitrary CW-complex X, generalizing the chromatic, tension and …

Ehrhart f*-coefficients of polytopal complexes are non-negative integers

F Breuer - arXiv preprint arXiv:1202.2652, 2012 - arxiv.org
The Ehrhart polynomial $ L_P $ of an integral polytope $ P $ counts the number of integer
points in integral dilates of $ P $. Ehrhart polynomials of polytopes are often described in …

Acyclotopes and Tocyclotopes

E Bach, M Beck, S Rehberg - arXiv preprint arXiv:2409.15227, 2024 - arxiv.org
There is a well-established dictionary between zonotopes, hyperplane arrangements, and
their (oriented) matroids. Arguably one of the most famous examples is the class of graphical …

Nowhere-zero flows in signed graphs: A survey

T Kaiser, E Rollová, R Lukot'ka - arXiv preprint arXiv:1608.06944, 2016 - arxiv.org
Nowhere-zero flows in signed graphs: A survey arXiv:1608.06944v1 [math.CO] 24 Aug 2016
Page 1 Nowhere-zero flows in signed graphs: A survey Tomáš Kaiser ∗ Robert Lukot’ka † Edita …

A simple algorithm that proves half‐integrality of bidirected network programming

ED Bolker, T Zaslavsky - Networks: An International Journal, 2006 - Wiley Online Library
In a bidirected graph, each end of each edge is independently oriented. We show how to
express any column of the incidence matrix as a half‐integral linear combination of any …