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Related papers: Tropical Methods in Hurwitz-Brill-Noether Theory

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A Laurent polynomial $f$ in two variables naturally describes a projective curve $C(f)$ on a toric surface. We show that if $C(f)$ is a smooth curve of genus at least 7, then $C(f)$ is not Brill-Noether general. To accomplish this, we…

Algebraic Geometry · Mathematics 2014-04-01 Geoffrey Degener Smith

In contrast to all other known Ramanujan-type congruences, we discover that Ramanujan-type congruences for Hurwitz class numbers can be supported on non-holomorphic generating series. We establish a divisibility result for such…

Number Theory · Mathematics 2022-05-25 Olivia Beckwith , Martin Raum , Olav K. Richter

An arrangement of finitely many tropical hyperplanes in the tropical torus leads to a notion of `type' data for points, with the underlying unlabeled arrangement giving rise to `coarse type'. It is shown that the decomposition of the…

Combinatorics · Mathematics 2013-01-21 Anton Dochtermann , Michael Joswig , Raman Sanyal

We present tools and definitions to study abstract tropical manifolds in dimension 2, which we call simply tropical surfaces. This includes explicit descriptions of intersection numbers of 1-cycles, normal bundles to some curves and…

Algebraic Geometry · Mathematics 2015-06-25 Kristin Shaw

We introduce and study a semigroup structure on the set of irreducible components of the Hurwitz space of marked coverings of a complex projective curve with given Galois group of the coverings and fixed ramification type. As application,…

Algebraic Geometry · Mathematics 2012-05-23 V. Kharlamov , Vik. Kulikov

This note is devoted to the definition of moduli spaces of rational tropical curves with n marked points. We show that this space has a structure of a smooth tropical variety of dimension n-3. We define the Deligne-Mumford compactification…

Algebraic Geometry · Mathematics 2007-05-23 Grigory Mikhalkin

In this present paper, we study the splitting of nodal plane curves with respect to contact conics. We define the notion of splitting type of such curves and show that it can be used as an invariant to distinguish the embedded topology of…

Algebraic Geometry · Mathematics 2016-08-22 Shinzo Bannai , Taketo Shirane

In tropical geometry, given a curve in a toric variety, one defines a corresponding graph embedded in Euclidean space. We study the problem of reversing this process for curves of genus zero and one. Our methods focus on describing curves…

Algebraic Geometry · Mathematics 2016-01-20 David E Speyer

The motivic nearby fiber is an invariant obtained from degenerating a complex variety over a disc. It specializes to the Euler characteristic of the original variety but also contains information on the variation of Hodge structure…

Algebraic Geometry · Mathematics 2021-10-05 Eric Katz , Alan Stapledon

This paper investigates the distribution of non-rigid families in a moduli space $\mathcal{M}$ of polarized projective manifolds for which the infinitesimal Torelli theorem holds. Guided by the analogy with unlikely intersection in Shimura…

Algebraic Geometry · Mathematics 2026-03-26 Ke Chen , Tianzhi Hu , Ruiran Sun , Kang Zuo

Given a lattice polygon, we study the moduli space of all tropical plane curves with that Newton polygon. We determine a formula for the dimension of this space in terms of combinatorial properties of that polygon. We prove that if this…

Algebraic Geometry · Mathematics 2025-10-01 Desmond Coles , Neelav Dutta , Sifan Jiang , Ralph Morrison , Andrew Scharf

We introduce a notion of tropical vector bundle on a tropical toric variety which is a tropical analogue of a torus equivariant vector bundle on a toric variety. Alternatively it can be called a toric matroid bundle. We define equivariant…

Algebraic Geometry · Mathematics 2024-08-15 Kiumars Kaveh , Christopher Manon

Rational curves on Hilbert schemes of points on $K3$ surfaces and generalised Kummer manifolds are constructed by using Brill-Noether theory on nodal curves on the underlying surface. It turns out that all wall divisors can be obtained, up…

Algebraic Geometry · Mathematics 2015-07-27 Andreas Leopold Knutsen , Margherita Lelli-Chiesa , Giovanni Mongardi

Hurwitz numbers count branched covers of the Riemann sphere with specified ramification data, or equivalently, transitive permutation factorizations in the symmetric group with specified cycle types. Monotone Hurwitz numbers count a…

Combinatorics · Mathematics 2019-08-15 I. P. Goulden , Mathieu Guay-Paquet , Jonathan Novak

We construct a natural branch divisor for equidimensional projective morphisms where the domain has lci singularities and the target is nonsingular. The method involves generalizing a divisor contruction of Mumford from sheaves to…

Algebraic Geometry · Mathematics 2007-05-23 B. Fantechi , R. Pandharipande

We study monotone and strictly monotone Hurwitz numbers from a bosonic Fock space perspective. This yields to an interpretation in terms of tropical geometry involving local multiplicities given by Gromov-Witten invariants. Furthermore,…

Algebraic Geometry · Mathematics 2019-01-03 Marvin Anas Hahn , Danilo Lewanski

For a convenient and Newton non-degenerate singularity, the Milnor number is computed from the complement of its Newton diagram in the first quadrant, so-called Kouchnirenko's formula. In this paper, we consider tropical curves dual to…

Algebraic Geometry · Mathematics 2016-09-07 Takuhiro Takahashi

A theorem of Chow concerns homomorphisms of two abelian varieties under a primary field extension base change. In this paper we generalize Chow's theorem to semi-abelian varieties. This contributes to different proofs of a well-known result…

Number Theory · Mathematics 2019-06-05 Chia-Fu Yu

Tropical geometry yields good lower bounds, in terms of certain combinatorial-polyhedral optimisation problems, on the dimensions of secant varieties. In particular, it gives an attractive pictorial proof of the theorem of Hirschowitz that…

Algebraic Geometry · Mathematics 2017-10-10 Jan Draisma

We explain a strategy for distinguishing Brill-Noether loci in the moduli space of curves by studying the lifting of linear systems on curves in polarized K3 surfaces, which motivates a conjecture identifying the maximal Brill-Noether loci…

Algebraic Geometry · Mathematics 2023-06-30 Asher Auel , Richard Haburcak