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We show that the mesh mutations are the minimal relations among the $\boldsymbol{g}$-vectors with respect to any initial seed in any finite type cluster algebra. We then use this algebraic result to derive geometric properties of the…

Representation Theory · Mathematics 2023-11-14 Arnau Padrol , Yann Palu , Vincent Pilaud , Pierre-Guy Plamondon

Spectral graph bisections are a popular heuristic aimed at approximating the solution of the NP-complete graph bisection problem. This technique, however, does not always provide a robust tool for graph partitioning. Using a special class…

Numerical Analysis · Mathematics 2015-12-22 John C. Urschel , Ludmil T. Zikatanov

Recent measurements have shown that a continuously tunable bandgap of up to 250 meV can be generated in biased bilayer graphene [Y. Zhang et al., Nature 459, 820 (2009)], opening up pathway for possible graphene-based nanoelectronic and…

Materials Science · Physics 2010-02-11 Cheol-Hwan Park , Steven G. Louie

We describe the structure of simplicial locally convex fans associated to even-dimensional complete toric varieties with signature 0. They belong to the set of such toric varieties whose even degree Betti numbers yield a top gamma vector…

Algebraic Geometry · Mathematics 2025-10-07 Soohyun Park

We introduce the notion of Lorentzian fans, which form a special class of tropical fans that are particularly well-suited for proving Alexandrov-Fenchel type inequalities. To demonstrate the utility of Lorentzian fans, we prove a practical…

Algebraic Geometry · Mathematics 2023-04-27 Dustin Ross

Viewing a fan as a partially ordered set (of cones) we consider a category of sheaves on the fan which corresponds to a category of equivariant sheaves on the corresponding toric variety if the fan is rational. In this category we define an…

Algebraic Geometry · Mathematics 2007-05-23 Paul Bressler , Valery A. Lunts

Normal complexes are orthogonal truncations of polyhedral fans. In this paper, we develop the study of mixed volumes for normal complexes. Our main result is a sufficiency condition that ensures when the mixed volumes of normal complexes…

Combinatorics · Mathematics 2023-01-16 Lauren Nowak , Patrick O'Melveny , Dustin Ross

We develop a tropical analogue of the classical double description method allowing one to compute an internal representation (in terms of vertices) of a polyhedron defined externally (by inequalities). The heart of the tropical algorithm is…

Computational Geometry · Computer Science 2011-12-30 Xavier Allamigeon , Stephane Gaubert , Eric Goubault

A powerful means to understanding condensed matter that possesses a multi-constituent, non-isolated, and complex nature, with a preeminent example being two-dimensional (2D) materials, is studying many-body interactions. However,…

We prove that the Chow ring of any simplicial fan is isomorphic to the middle degree part of the tropical cohomology ring of its canonical compactification. Using this result, we prove a tropical analogue of Kleiman's criterion of ampleness…

Algebraic Geometry · Mathematics 2024-05-09 Omid Amini , Matthieu Piquerez

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 explicate the combinatorial/geometric ingredients of Arthur's proof of the convergence and polynomiality, in a truncation parameter, of his non-invariant trace formula. Starting with a fan in a real, finite dimensional, vector space and…

Number Theory · Mathematics 2024-10-07 Mahdi Asgari , Kiumars Kaveh

We construct an explicit bijection between bipartite pointed maps of an arbitrary surface $\mathbb{S}$, and specific unicellular blossoming maps of the same surface. Our bijection gives access to the degrees of all the faces, and distances…

Combinatorics · Mathematics 2022-08-02 Maciej Dołęga , Mathias Lepoutre

Hohlweg and Lange (2007) and Santos (2004, unpublished) have found two different ways of constructing exponential families of realizations of the n-dimensional associahedron with normal vectors in {0,1,-1}^n, generalizing the constructions…

Metric Geometry · Mathematics 2016-02-08 Cesar Ceballos , Francisco Santos , Günter M. Ziegler

In this paper we provide a framework for the study of isoperimetric problems in finitely generated group, through a combinatorial study of universal covers of compact simplicial complexes. We show that, when estimating filling functions,…

Geometric Topology · Mathematics 2015-07-07 Jason Behrstock , Cornelia Drutu

In Lorentzian geometry, limited definition of angles restricts the use of angle bisectors in study of triangles. This paper redefines angle bisectors so that they can be used to study attributes of triangles. Using the new definition, this…

Differential Geometry · Mathematics 2014-04-25 Joseph Cho

The bisection width of interconnection networks has always been important in parallel computing, since it bounds the amount of information that can be moved from one side of a network to another, i.e., the bisection bandwidth. Finding its…

Networking and Internet Architecture · Computer Science 2012-02-29 Jordi Arjona Aroca , Antonio Fernández Anta

A new class of full fans in an euclidean space - tight fans - is introduced. Such fans are defined using a property of local symmetry in a face of a tiling. Tight fans are related to the theory of parallelotopes in an euclidean space. A…

Metric Geometry · Mathematics 2016-03-08 Andrei Gavrilyuk

A (convex) polytope $P$ is said to be $2$-level if for every direction of hyperplanes which is facet-defining for $P$, the vertices of $P$ can be covered with two hyperplanes of that direction. The study of these polytopes is motivated by…

We introduce a moduli functor for varieties whose tropicalization realizes a given weighted fan and show that this functor is an algebraic space in general, and is represented by a scheme of finite type when the associated toric variety is…

Algebraic Geometry · Mathematics 2012-03-30 Eric Katz , Sam Payne