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Tropical counting tools are useful for many enumerative questions. We count tropical multinodal surfaces using floor plans, looking at the case when two nodes are tropically close together, i.e., unseparated. We generalize tropical floor…

Algebraic Geometry · Mathematics 2022-12-16 Madeline Brandt , Alheydis Geiger

Given a vertex-coloured graph, a dominating set is said to be tropical if every colour of the graph appears at least once in the set. Here, we study minimum tropical dominating sets from structural and algorithmic points of view. First, we…

Discrete Mathematics · Computer Science 2016-01-19 J. -A. Angles d'Auriac , Cs. Bujtas , A. El Maftouhi , M. Karpinski , Y. Manoussakis , L. Montero , N. Narayanan , L. Rosaz , J. Thapper , Zs. Tuza

We present a concept called the branch-depth of a connectivity function, that generalizes the tree-depth of graphs. Then we prove two theorems showing that this concept aligns closely with the notions of tree-depth and shrub-depth of graphs…

Combinatorics · Mathematics 2020-11-05 Matt DeVos , O-joung Kwon , Sang-il Oum

We prove a general duality theorem for tangle-like dense objects in combinatorial structures such as graphs and matroids. This paper continues, and assumes familiarity with, the theory developed in [6]

Combinatorics · Mathematics 2014-06-17 Reinhard Diestel , Sang-il Oum

There are many notions of rank in multilinear algebra: tensor rank, partition rank, slice rank, and strength (or Schmidt rank) are a few examples. Typically the rank $\le r$ locus is not Zariski closed, and understanding the closure (the…

Algebraic Geometry · Mathematics 2024-02-21 Arthur Bik , Jan Draisma , Rob Eggermont , Andrew Snowden

This article emphasizes an extension of the study of metric and par- tition dimension to hypergraphs. We give a sharp lower bounds for the metric and partition dimension of hypergraphs in general and give exact values under specified…

Combinatorics · Mathematics 2024-06-18 Imran Javaid , Azeem Haider , Muhammad Salman , Sadaf Mehtab

In this paper we study Cartesian products of graphs and their divisorial gonality, which is a tropical version of the gonality of an algebraic curve. We present an upper bound on the gonality of the Cartesian product of any two graphs, and…

Combinatorics · Mathematics 2019-09-24 Ivan Aidun , Ralph Morrison

We study the conjecture stated by Jensen and Len on a tropical version on Martens' theorem via the Brill--Noether rank of a tropical curve. We recall Coppens' counterexample of Martens-special chain of cycles, and we generalize the…

Combinatorics · Mathematics 2025-12-16 Giusi Capobianco , Angelina Zheng

We show that all the tangles in a finite graph or matroid can be distinguished by a single tree-decomposition that is invariant under the automorphisms of the graph or matroid. This comes as a corollary of a similar decomposition theorem…

Combinatorics · Mathematics 2017-04-19 Reinhard Diestel , Fabian Hundertmark , Sahar Lemanczyk

Recently, it was proved by B\'erczi and Schwarcz that the problem of factorizing a matroid into rainbow bases with respect to a given partition of its ground set is algorithmically intractable. On the other hand, many special cases were…

Combinatorics · Mathematics 2023-05-30 Florian Hörsch , Tomáš Kaiser , Matthias Kriesell

We investigate the tree gonality of a genus-$g$ metric graph, defined as the minimum degree of a tropical morphism from any tropical modification of the metric graph to a metric tree. We give a combinatorial constructive proof that this…

Combinatorics · Mathematics 2020-07-31 Jan Draisma , Alejandro Vargas

In analogy with the Manin-Mumford conjecture for algebraic curves, one may ask how a metric graph under the Abel-Jacobi embedding intersects torsion points of its Jacobian. We show that the number of torsion points is finite for metric…

Algebraic Geometry · Mathematics 2023-10-12 David Harry Richman

Universality theorems (in the sense of N. Mn\"{e}v) claim that the realization space of a combinatorial object (a point configuration, a hyperplane arrangement, a convex polytope, etc.) can be arbitrarily complicated. In the paper, we prove…

Combinatorics · Mathematics 2019-10-30 Gaiane Panina

A biased graph is a graph with a class of selected circles ("cycles", "circuits"), called "balanced", such that no theta subgraph contains exactly two balanced circles. A biased graph has two natural matroids, the frame matroid and the lift…

Combinatorics · Mathematics 2021-06-16 Rigoberto Flórez , Thomas Zaslavsky

In this paper, we study tropical Weierstrass points. These are the analogues for tropical curves of ramification points of line bundles on algebraic curves. For a divisor on a tropical curve, we associate intrinsic weights to the connected…

Algebraic Geometry · Mathematics 2026-03-27 Omid Amini , Lucas Gierczak , Harry Richman

The Dowling geometry $Q_n(\Gamma)$, where $\Gamma$ is a finite group, is a matroid that generalizes the complete-graphic matroid $M(K_{n+1})$. We determine the maximum size of an $N$-free submatroid of $Q_n(\Gamma)$ for various choices of…

Combinatorics · Mathematics 2025-11-25 Rutger Campbell , Donggyu Kim , Jorn van der Pol

We propose a generalization of tropical curves by dropping the rationality and integrality requirements while preserving the balancing condition. An interpretation of such curves as critical points of a certain quadratic functional allows…

Algebraic Geometry · Mathematics 2018-12-04 Sergei Lanzat , Michael Polyak

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 characterize the class of threshold matroids by the structure of their defining bases. We also give an example of a shifted matroid which is not threshold, answering a question of Deza and Onn. We conclude by exploring consequences of…

Combinatorics · Mathematics 2025-09-01 Ethan Partida

Tropical curves in $\mathbb{R}^2$ correspond to metric planar graphs but not all planar graphs arise in this way. We describe several new classes of graphs which cannot occur. For instance, this yields a full combinatorial characterization…

Combinatorics · Mathematics 2021-08-03 Michael Joswig , Ayush Kumar Tewari
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