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We give several characterizations of stable intersections of tropical cycles and establish their fundamental properties. We prove that the stable intersection of two tropical varieties is the tropicalization of the intersection of the…

Algebraic Geometry · Mathematics 2016-08-12 Anders Jensen , Josephine Yu

We extend the tropical intersection theory to tropicalizations of germs of analytic sets. In particular, we construct a (not entirely obvious) local version of the ring of tropical fans with a nondegenerate intersection pairing. As an…

Algebraic Geometry · Mathematics 2021-09-22 Alexander Esterov

We give an affirmative answer to a conjecture proposed by Tevelev in characteristic 0 case: any variety contains a sch\"on very affine open subvariety. Also we show that any fan supported on the tropicalization of a sch\"on very affine…

Algebraic Geometry · Mathematics 2009-02-13 Mark Luxton , Zhenhua Qu

Artin fans are algebro-geometric incarnations of cone complexes. We study weakly convex Olsson fans, generalising Artin fans in two ways: first, they admit lineality spaces, thus including tropical tori as well; second, they are defined…

Algebraic Geometry · Mathematics 2026-02-06 Luca Battistella , Francesca Carocci , Jonathan Wise

We study the category of KM fans - a "stacky" generalization of the category of fans considered in toric geometry - and its various realization functors to "geometric" categories. The "purest" such realization takes the form of a functor…

Algebraic Geometry · Mathematics 2015-12-24 W. D. Gillam , Sam Molcho

We apply a Mayer-Vietoris sequence argument to identify the Atiyah-Segal equivariant complex K-theory rings of certain toric varieties with rings of integral piecewise Laurent polynomials on the associated fans. We provide necessary and…

K-Theory and Homology · Mathematics 2018-08-02 Tara S. Holm , Gareth Williams

This note which can be viewed as a complement to Alex Postnikov's paper math.CO/0507163, presents a self-contained overview of basic properties of nested complexes and their two dual polyhedral realizations: as complete simplicial fans, and…

Combinatorics · Mathematics 2007-05-23 Andrei Zelevinsky

We provide an overview of the combinatorial theory of horospherical varieties using coloured fans, a generalization of the combinatorial theory of toric varieties using polyhedral fans.

Algebraic Geometry · Mathematics 2026-03-04 Sean Monahan

We investigate the equivariant intersection cohomology of a toric variety. Considering the defining fan of the variety as a finite topological space with the subfans being the open sets (that corresponds to the "toric" topology given by the…

Algebraic Geometry · Mathematics 2007-05-23 Gottfried Barthel , Jean-Paul Brasselet , Karl-Heinz Fieseler , Ludger Kaup

The goal of this paper is to show that the local Gr\"obner fan is a polyhedral fan for ideals in the ring of power series and the homogenized ring of analytic differential operators. We will also discuss about relations between the local…

Algebraic Geometry · Mathematics 2007-05-23 Rouchdi Bahloul , Nobuki Takayama

The purpose of this article is to develop foundational techniques from logarithmic geometry in order to define a functorial tropicalization map for fine and saturated logarithmic schemes in the case of constant coefficients. Our approach…

Algebraic Geometry · Mathematics 2017-06-14 Martin Ulirsch

The theta--fan F_theta is the quotient space obtained by identifying the non--isolated points of the product theta \times (omega+1) with a single point \infty. (Here, theta has the discrete topology and omega+1 has the order topology.) We…

Logic · Mathematics 2016-09-06 Jörg Brendle , Tim LaBerge

We extend tropicalization and tropical compactification of subvarieties of algebraic tori to subvarieties of spherical homogeneous spaces. Given a tropical compactification of a subvariety, we show that the support of the colored fan of the…

Algebraic Geometry · Mathematics 2020-08-31 Jenia Tevelev , Tassos Vogiannou

The purpose of this article is to study the role of Artin fans in tropical and non-Archimedean geometry. Artin fans are logarithmic algebraic stacks that can be described completely in terms of combinatorial objects, so called Kato stacks,…

Algebraic Geometry · Mathematics 2018-12-27 Martin Ulirsch

The Lelek fan is the only smooth fan that has a dense set of end-points. In this paper, we study non-smooth fans with this property; i.e., we construct an uncountable family of pairwise non-homeomorphic such fans. Furthermore, we prove that…

Dynamical Systems · Mathematics 2025-05-08 Iztok Banic , Goran Erceg , Ivan Jelic , Judy Kennedy

The space of torus translations and degenerations of a projective toric variety forms a toric variety associated to the secondary fan of the integer points in the polytope corresponding to the toric variety. This is used to identify a…

Algebraic Geometry · Mathematics 2020-12-22 Ata Pir , Frank Sottile

We introduce the notion of tropical Lagrangian multi-sections over a fan and study its relation with toric vector bundles. We also introduce a "SYZ-type" construction for toric vector bundles which gives a reinterpretation of Kaneyama's…

Algebraic Geometry · Mathematics 2023-11-08 Yat-Hin Suen

In this article we introduce a notion of normalized angle for Lorentzian pre-length spaces. This concept allows us to prove some equivalences to the definition of timelike curvature bounds from below for Lorentzian pre-length spaces.…

Differential Geometry · Mathematics 2022-09-28 Waldemar Barrera , Luis Montes de Oca , Didier A. Solis

Normal toric varieties over a field or a discrete valuation ring are classified by rational polyhedral fans. We generalize this classification to normal toric varieties over an arbitrary valuation ring of rank one. The proof is based on a…

Algebraic Geometry · Mathematics 2015-01-30 Walter Gubler , Alejandro Soto

For any lattice congruence of the weak order on permutations, N. Reading proved that gluing together the cones of the braid fan that belong to the same congruence class defines a complete fan, called a quotient fan, and V. Pilaud and F.…

Combinatorics · Mathematics 2023-11-14 Arnau Padrol , Vincent Pilaud , Julian Ritter