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Scaffolds are the one-dimensional skeleta of high-dimensional flag simplicial complexes of nonpositive curvature. They generalize the phylogenetic trees of Trop G(2,n) to arbitrary $k$, drawing together SL(k)-web bases, affine buildings,…

Combinatorics · Mathematics 2026-04-29 Nick Early , Thomas Lam

In tropical algebraic geometry, the solution sets of polynomial equations are piecewise-linear. We introduce the tropical variety of a polynomial ideal, and we identify it with a polyhedral subcomplex of the Grobner fan. The tropical…

Algebraic Geometry · Mathematics 2007-05-23 David Speyer , Bernd Sturmfels

Tropical algebraic geometry is the geometry of the tropical semiring (R, min, +). The theory of total positivity is a natural generalization of the study of matrices with all minors positive. In this paper we introduce the totally positive…

Combinatorics · Mathematics 2007-05-23 David Speyer , Lauren K. Williams

We give a complete description of Green's D relation for the multiplicative semigroup of all n-by-n tropical matrices. Our main tool is a new variant on the duality between the row and column space of a tropical matrix (studied by Cohen,…

Rings and Algebras · Mathematics 2014-02-26 Christopher Hollings , Mark Kambites

We introduce combinatorial objects which are parameterized by the positive part of the tropical Grassmannian $Gr(k,n)$. Our method is to relate the Grassmannian to configuration spaces of flags. By work of the first author, and of Goncharov…

Algebraic Geometry · Mathematics 2017-10-16 Chris Fraser , Ian Le

The nonnegative Grassmannian is a cell complex with rich geometric, algebraic, and combinatorial structures. Its study involves interesting combinatorial objects, such as positroids and plabic graphs. Remarkably, the same combinatorial…

Combinatorics · Mathematics 2018-06-15 Alexander Postnikov

In this paper, we continue our study of blade arrangements and the positroidal subdivisions which are induced by them on $\Delta_{k,n}$. A blade is a tropical hypersurface which is generated by a system of $n$ affine simple roots of type…

Combinatorics · Mathematics 2022-10-14 Nick Early

We study the classical result by Bruijn and Erd\H os regarding the bound on the number of lines determined by a $n$-point configuration in the plane, and in the light of the recently proven Tropical Sylvester-Gallai theorem, come up with a…

Algebraic Geometry · Mathematics 2020-06-09 Ayush Kumar Tewari

Tropical geometry with the max-plus algebra has been applied to statistical learning models over tree spaces because geometry with the tropical metric over tree spaces has some nice properties such as convexity in terms of the tropical…

Combinatorics · Mathematics 2021-11-02 Ruriko Yoshida , Shelby Cox

We launch the study of the tropicalization of the symplectic Grassmannian, that is, the space of all linear subspaces that are isotropic with respect to a fixed symplectic form. We formulate tropical analogues of several equivalent…

Combinatorics · Mathematics 2021-10-18 George Balla , Jorge Alberto Olarte

We show that the tropical projective Grassmannian of planes is homeomorphic to a closed subset of the analytic Grassmannian in Berkovich's sense by constructing a continuous section to the tropicalization map. Our main tool is an explicit…

Algebraic Geometry · Mathematics 2014-03-12 Maria Angelica Cueto , Mathias Haebich , Annette Werner

The Dressian and the tropical Grassmannian parameterize abstract and realizable tropical linear spaces; but in general, the Dressian is much larger than the tropical Grassmannian. There are natural positive notions of both of these spaces…

Combinatorics · Mathematics 2020-03-24 David Speyer , Lauren K. Williams

Recent developments in particle physics have revealed deep connections between scattering amplitudes and tropical geometry. From the heart of this relationship emerged the chirotropical Grassmannian $\text{Trop}^\chi \text{G}(k,n)$ and the…

Combinatorics · Mathematics 2025-11-25 Dario Antolini , Nick Early

Tropical geometry and the theory of Newton-Okounkov bodies are two methods which produce toric degenerations of an irreducible complex projective variety. Kaveh-Manon showed that the two are related. We give geometric maps between the…

Algebraic Geometry · Mathematics 2021-07-05 Laura Escobar , Megumi Harada

In this article, we present a massively parallel framework for computing tropicalizations of algebraic varieties which can make use of finite symmetries. We compute the tropical Grassmannian TGr$_0(3,8)$, and show that it refines the…

Algebraic Geometry · Mathematics 2020-04-02 Dominik Bendle , Janko Boehm , Yue Ren , Benjamin Schröter

We study a natural generalization of the noncrossing relation between pairs of elements in [n] to k-tuples in [n] that was first considered by Petersen, Pylyavskyy, Speyer (2010). We give an alternative approach to their result that the…

Combinatorics · Mathematics 2017-02-23 Francisco Santos , Christian Stump , Volkmar Welker

We study the locus of tropical hyperelliptic curves inside the moduli space of tropical curves of genus g. We define a harmonic morphism of metric graphs and prove that a metric graph is hyperelliptic if and only if it admits a harmonic…

Combinatorics · Mathematics 2011-10-04 Melody Chan

We study the totally non-negative part of the complete flag variety and of its tropicalization. We start by showing that Lusztig's notion of non-negative complete flag variety coincides with the flags in the complete flag variety which have…

Combinatorics · Mathematics 2021-11-25 Jonathan Boretsky

The Dressian Dr(k,n) parametrizes all tropical linear spaces, and it carries a natural fan structure as a subfan of the secondaryfan of the hypersimplex \Delta(k,n). We explore the combinatorics of the rays of Dr(k,n), that is, the most…

Combinatorics · Mathematics 2015-03-19 Sven Herrmann , Michael Joswig , David Speyer

The goal of this paper is to make a connection between tropical geometry, representations of quantum affine algebras, and scattering amplitudes in physics. The connection allows us to study important and difficult questions in these areas:…

Quantum Algebra · Mathematics 2024-04-16 Nick Early , Jian-Rong Li
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