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Related papers: A Riemann-Roch theorem in tropical geometry

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We consider a variant of metrised graphs where the edge lengths take values in a commutative monoid, as a higher-rank generalisation of the notion of a tropical curve. Divisorial gonality, which Baker and Norine defined on combinatorial…

Combinatorics · Mathematics 2022-09-19 Josse van Dobben de Bruyn , David Holmes , David van der Vorm

We use the tropical geometry approach to compute absolute and relative Gromov-Witten invariants of complex surfaces which are $\CC P^1$-bundles over an elliptic curve. We also show that the tropical multiplicity used to count curves can be…

Algebraic Geometry · Mathematics 2022-12-14 Thomas Blomme

The comparison theory for the Riccati equation satisfied by the shape operator of parallel hypersurfaces is generalized to semi-Riemannian manifolds of arbitrary index, using one-sided bounds on the Riemann tensor which in the Riemannian…

dg-ga · Mathematics 2008-02-03 L. Andersson , R. Howard

Elements of the tropical vertex group, introduced by Kontsevich and Soibelman, are formal families of symplectomorphisms of the 2-dimensional algebraic torus. We prove ordered product factorizations in the tropical vertex group are…

Algebraic Geometry · Mathematics 2019-12-19 Mark Gross , Rahul Pandharipande , Bernd Siebert

This is a follow-up paper of arXiv:1805.00115, where rational curves in surfaces that satisfy general positioned point and cross-ratio conditions were enumerated. A suitable correspondence theorem provided in arXiv:1509.07453 allowed us to…

Algebraic Geometry · Mathematics 2020-03-24 Christoph Goldner

In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well studied Pascal graphs and Toeplitz graphs, and also some other…

Combinatorics · Mathematics 2019-04-16 Gi-Sang Cheon , Ji-Hwan Jung , Sergey Kitaev , Seyed Ahmad Mojallal

We prove results generalizing the classical Riemann Singularity Theorem to the case of integral, singular curves. The main result is a computation of the multiplicity of the theta divisor of an integral, nodal curve at an arbitrary point.…

Algebraic Geometry · Mathematics 2015-03-13 Sebastian Casalaina-Martin , Jesse Leo Kass

We prove a Reeb sphere theorem for finite simple graphs. The result bridges two different definitions of spheres in graph theory. We also reformulate Morse conditions in terms of the center manifolds, the level surface graphs {f=f(x)} in…

Combinatorics · Mathematics 2019-03-26 Oliver Knill

We construct a space classifying divisor classes of a fixed degree on all tropical curves of a fixed combinatorial type and show that the function taking a divisor class to its rank is upper semicontinuous. We extend the definition of the…

Algebraic Geometry · Mathematics 2014-04-02 Yoav Len

Patchworking theorems serve as a basic element of the correspondence between tropical and algebraic curves, which is a core of the tropical enumerative geometry. We present a new version of a patchworking theorem which relates plane…

Algebraic Geometry · Mathematics 2009-11-01 Eugenii Shustin

The Riemann-Roch Theorem is one of the cornerstones of algebraic geometry, connecting algebraic data (sheaf cohomology) with geometric ones (intersection theory). This survey paper provides a self-contained introduction and a complete proof…

Algebraic Geometry · Mathematics 2025-11-19 Giacomo Graziani

We give yet another proof of the list-color version of Brooks' theorem that is due, independently, to Vizing and to Erd\H{o}s, Rubin and Taylor, via a famous theorem of Dirac on chordal graphs.

Combinatorics · Mathematics 2023-09-22 Carl Feghali

In this note, we use Rouch\'e's theorem and the pleasant properties of the arithmetic of the logarithmic derivative to establish several new results regarding the geometry of the zeros, poles, and critical points of a rational function.…

Complex Variables · Mathematics 2019-06-13 Trevor J. Richards

In this paper we generalize correspondence theorems of Mikhalkin and Nishinou-Siebert providing a correspondence between algebraic and parameterized tropical curves. We also give a description of a canonical tropicalization procedure for…

Algebraic Geometry · Mathematics 2011-07-12 Ilya Tyomkin

We enumerate rational curves in toric surfaces passing through points and satisfying cross-ratio constraints using tropical and combinatorial methods. Our starting point is arXiv:1509.07453, where a tropical-algebraic correspondence theorem…

Algebraic Geometry · Mathematics 2018-05-02 Christoph Goldner

We generalize the H. Cartan's theory of holomorphic curves for a general open Riemann surface. Besides, a vanishing theorem for jet differentials and a Bloch's theorem for Riemann surfaces are obtained.

Complex Variables · Mathematics 2021-05-25 Xianjing Dong

We prove the Riemann-Roch theorem for homotopy invariant $K$-theory and projective local complete intersection morphisms between finite dimensional noetherian schemes, without smoothness assumptions. We also prove a new Riemann-Roch theorem…

K-Theory and Homology · Mathematics 2016-05-04 Alberto Navarro

In the paper, we give a Schur-Toponogov theorem in Riemannian geometry, which not only generalizes Schur's and Toponogov's theorem but also indicates their relation. Inspired by its proof, we also supply a new proof of Toponogov's theorem…

Differential Geometry · Mathematics 2020-03-20 Yusheng Wang

We generalize the classical de Rham decomposition theorem for Riemannian manifolds to the setting of geodesic metric spaces of finite dimension.

Metric Geometry · Mathematics 2007-05-23 Thomas Foertsch , Alexander Lytchak

We study a notion of curvature for finitely generated groups which serves as a role of Ricci curvature for Riemannian manifolds. We prove an analog of Cheeger-Gromoll splitting theorem. As a consequence, we give a geometric characterization…

Group Theory · Mathematics 2023-02-15 Thang Nguyen , Shi Wang