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The Bergman fan of a matroid is the intersection of tropical hyperplanes defined by the circuits. A tropical basis is a subset of the circuits set that defines the Bergman fan. Yu and Yuster posed a question whether every simple regular…

Combinatorics · Mathematics 2019-02-22 Yasuhito Nakajima

Given a matroid M on the ground set E, the Bergman fan B(M), or space of M-ultrametrics, is a polyhedral complex in R^E which arises in several different areas, such as tropical algebraic geometry, dynamical systems, and phylogenetics.…

Combinatorics · Mathematics 2007-05-23 Federico Ardila

In this paper, we consider weighted counts of tropical plane curves of particular combinatorial type through a certain number of generic points. We give a criterion, derived from tropical intersection theory on the secondary fan, for a…

Algebraic Geometry · Mathematics 2012-06-18 Eric Katz

Every tropical ideal in the sense of Maclagan-Rinc\'on has an associated tropical variety, a finite polyhedral complex equipped with positive integral weights on its maximal cells. This leads to the realisability question, ubiquitous in…

Combinatorics · Mathematics 2021-06-29 Jan Draisma , Felipe Rincón

We express the beta invariant of a loopless matroid as tropical self-intersection number of the diagonal of its matroid fan (a "local" Poincar\'e-Hopf theorem). This provides another example of uncovering the "geometry" of matroids by…

Algebraic Geometry · Mathematics 2023-02-22 Johannes Rau

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

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 varieties play an important role in algebraic geometry. The Bergman complex B(M) and the positive Bergman complex B+(M) of an oriented matroid M generalize to matroids the notions of the tropical variety and positive tropical…

Combinatorics · Mathematics 2007-05-23 Federico Ardila , Victor Reiner , Lauren Williams

In this paper we investigate the idea of a tropical critical point of the superpotential for the full flag variety of type A. Recall that associated to an irreducible representation of G=SLn(C) are various polytopes whose integral points…

Algebraic Geometry · Mathematics 2017-08-10 Jamie Judd

Let D(m,n) be the set of all the integer points in the m-dilate of the Birkhoff polytope of doubly-stochastic n by n matrices. In this paper we find the sharp upper bound on the tropical determinant over the set D(m,n). We define a version…

Combinatorics · Mathematics 2012-02-03 Thomas Dinitz , Matthew Hartman , Jenya Soprunova

The celebrated upper bound theorem of McMullen determines the maximal number of extreme points of a polyhedron in terms of its dimension and the number of constraints which define it, showing that the maximum is attained by the polar of the…

Combinatorics · Mathematics 2010-11-04 Xavier Allamigeon , Stephane Gaubert , Ricardo D. Katz

We consider toric maximum likelihood estimation over the field of Puiseux series and study critical points of the likelihood function using tropical methods. This problem translates to finding the intersection points of a tropical affine…

Algebraic Geometry · Mathematics 2025-08-08 Emma Boniface , Karel Devriendt , Serkan Hoşten

We study a rational matroid invariant, obtained as the tropicalization of the Feynman period integral. It equals the volume of the polar of the matroid polytope and we give efficient formulas for its computation. This invariant is proven to…

Mathematical Physics · Physics 2023-05-16 Erik Panzer

We construct an intersection product on tropical cycles contained in the Bergman fan of a matroid. To do this we first establish a connection between the operations of deletion and restriction in matroid theory and tropical modifications as…

Algebraic Geometry · Mathematics 2011-10-05 Kristin M. Shaw

The critical threshold of a (simple binary) matroid $N$ is the infimum over all $\rho$ such that any $N$-free matroid $M$ with $|M|>\rho2^{r(M)}$ has bounded critical number. In this paper, we resolve two conjectures of Geelen and Nelson,…

Combinatorics · Mathematics 2017-09-06 Jonathan Tidor

We study the positive Bergman complex B+(M) of an oriented matroid M, which is a certain subcomplex of the Bergman complex B(M) of the underlying unoriented matroid. The positive Bergman complex is defined so that given a linear ideal I…

Combinatorics · Mathematics 2007-05-23 Federico Ardila , Caroline Klivans , Lauren Williams

We compute the critical polymials for the q-state Potts model on all Archimedean lattices, using a parallel implementation of the algorithm of (Jacobsen, J. Phys. A: Math. Theor. 47 135001) that gives us access to larger sizes than…

Statistical Mechanics · Physics 2015-11-16 Christian R. Scullard , Jesper Lykke Jacobsen

We study a notion of tropical linear series on metric graphs that combines two essential properties of tropicalizations of linear series on algebraic curves: the Baker-Norine rank and the independence rank. Our main results relate the local…

Algebraic Geometry · Mathematics 2025-09-05 Chih-Wei Chang , Matthew Dupraz , Hernan Iriarte , David Jensen , Dagan Karp , Sam Payne , Jidong Wang

We prove that the proper amalgam of matroids $M_1$ and $M_2$ along their common restriction $N$ exists if and only if the tropical fibre product of Bergman fans ${B(M_1) \times_{B(N)} B(M_2)}$ is positive. We introduce tropical…

Algebraic Geometry · Mathematics 2024-04-30 Dmitry Mineev

We give a characterization of the percolation threshold for a multirange model on oriented trees, as the first positive root of a polynomial, with the use of a multi-type Galton-Watson process. This gives in particular the exact value of…

Probability · Mathematics 2025-12-11 Olivier Couronné
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