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The map which takes a square matrix to its tropical eigenvalue-eigenvector pair is piecewise linear. We determine the cones of linearity of this map. They are simplicial but they do not form a fan. Motivated by statistical ranking, we also…

Combinatorics · Mathematics 2014-02-26 Bernd Sturmfels , Ngoc Mai Tran

The tropical Stiefel map associates to a tropical matrix A its tropical Pluecker vector of maximal minors, and thus a tropical linear space L(A). We call the L(A)s obtained in this way Stiefel tropical linear spaces. We prove that they are…

Combinatorics · Mathematics 2015-06-02 Alex Fink , Felipe Rincón

Polytropes are both ordinary and tropical polytopes. We show that tropical types of polytropes in $\mathbb{TP}^{n-1}$ are in bijection with cones of a certain Gr\"{o}bner fan $\mathcal{GF}_n$ in $\mathbb{R}^{n^2 - n}$ restricted to a small…

Combinatorics · Mathematics 2016-04-12 Ngoc Mai Tran

We define and study the cyclic Bergman fan of a matroid M, which is a simplicial polyhedral fan supported on the tropical linear space T(M) of M and is amenable to computational purposes. It slightly refines the nested set structure on…

Combinatorics · Mathematics 2013-03-07 Felipe Rincón

Tropical polyhedra are known to be representable externally, as intersections of finitely many tropical half-spaces. However, unlike in the classical case, the extreme rays of their polar cones provide external representations containing in…

Combinatorics · Mathematics 2013-02-14 Xavier Allamigeon , Ricardo D. Katz

The spinor variety is cut out by the quadratic Wick relations among the principal Pfaffians of an n x n skew-symmetric matrix. Its points correspond to n-dimensional isotropic subspaces of a 2n-dimensional vector space. In this paper we…

Combinatorics · Mathematics 2013-03-07 Felipe Rincón

We study the subgroup structure of the semigroup of finitary tropical matrices under multiplication. We show that every maximal subgroup is isomorphic to the full linear automorphism group of a related tropical polytope, and that each of…

Group Theory · Mathematics 2012-03-13 Zur Izhakian , Marianne Johnson , Mark Kambites

We undertake a combinatorial study of the piecewise linear map g : R^{2m+2n} --> R^{mn} which assigns to the four vectors a, A in R^m and b, B in R^n the m by n matrix given by g_{ij} = min (a_i + b_j, A_i+B_j). This map arises naturally in…

Combinatorics · Mathematics 2007-05-23 Federico Ardila

In this paper, we classify singular real plane tropical curves by means of subdivisions of Newton polytopes. First, we introduce signed Bergman fans (generalizing positive Bergman fans from [AKW06]) that describe real tropicalizations of…

Algebraic Geometry · Mathematics 2018-02-07 Christian Jürgens

A polytrope is a tropical polyhedron that is also classically convex. We study the tropical combinatorial types of polytropes associated to weighted directed acyclic graphs (DAGs). This family of polytropes arises in algebraic statistics…

Combinatorics · Mathematics 2025-10-16 Carlos Améndola , Kamillo Ferry

This paper is about the combinatorics of finite point configurations in the tropical projective space or, dually, of arrangements of finitely many tropical hyperplanes. Moreover, arrangements of finitely many tropical halfspaces can be…

Combinatorics · Mathematics 2019-06-21 Michael Joswig , Georg Loho

For an $n \times n$ nonnegative matrix $P$, an isomorphism is obtained between the lattice of initial subsets (of ${1,...,n}$) for $P$ and the lattice of $P$-invariant faces of the nonnegative orthant $\IR^{n}_{+}$. Motivated by this…

Rings and Algebras · Mathematics 2007-05-23 Bit-Shun Tam , Hans Schneider

We describe a canonical compactification of a polyhedral complex in Euclidean space. When the recession cones of the polyhedral complex form a fan, the compactified polyhedral complex is a subspace of a tropical toric variety. In this case,…

Algebraic Geometry · Mathematics 2020-12-23 Lars Kastner , Kristin Shaw , Anna-Lena Winz

We define tropical analogues of the notions of linear space and Plucker coordinate and study their combinatorics. We introduce tropical analogues of intersection and dualization and define a tropical linear space built by repeated…

Combinatorics · Mathematics 2007-05-23 David E Speyer

For any lattice congruence of the weak order on $\mathfrak{S}_n$, N. Reading proved that glueing together the cones of the braid fan that belong to the same congruence class defines a complete fan. We prove that this fan is the normal fan…

Combinatorics · Mathematics 2019-06-04 Vincent Pilaud , Francisco Santos

Smooth tropical cubic surfaces are parametrized by maximal cones in the unimodular secondary fan of the triple tetrahedron. There are $344\, 843 \,867$ such cones, organized into a database of $14\,373\,645$ symmetry classes. The Schl\"afli…

Combinatorics · Mathematics 2021-08-03 Michael Joswig , Marta Panizzut , Bernd Sturmfels

Given a tree $T$, its path polytope is the convex hull of the edge indicator vectors for the paths between any two distinct leaves in $T$. These polytopes arise naturally in polyhedral geometry and applications, such as phylogenetics,…

Combinatorics · Mathematics 2025-03-03 Amer Goel , Aida Maraj , Alvaro Ribot

We consider arrangements of tropical hyperplanes where the apices of the hyperplanes are taken to infinity in certain directions. Such an arrangement defines a decomposition of Euclidean space where a cell is determined by its `type' data,…

Commutative Algebra · Mathematics 2025-02-21 Ayah Almousa , Anton Dochtermann , Ben Smith

A biconvex polytope is a classical and tropical convex hull of finitely many points. Given a biconvex polytope, for each vertex of it we construct a directed bigraph and a gammoid so that the collection of base polytopes of those gammoids…

Algebraic Geometry · Mathematics 2022-12-21 Jaeho Shin

Given a dissimilarity map $\delta$ on finite set $X$, the set of ultrametrics (equidistant tree metrics) which are $l^\infty$-nearest to $\delta$ is a tropical polytope. We give an internal description of this tropical polytope which we use…

Combinatorics · Mathematics 2019-12-24 Daniel Irving Bernstein
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