arXiv subjects

Eduardo Vital

Publications and source records attributed to Eduardo Vital.

8 recordsLinked to original sources

arXiv2026

On the Hilbert polynomial of the linked projective space

Linked projective spaces are quiver Grassmannians of subspaces of dimension 1 of certain quiver representations. Degenerations of linear series produce these representations, with the limit divisors parameterized by the associated linked projective spaces. It is not known whether all linked projective spaces arise this way. If they do, they are degenerations of the (small) diagonal in a product of projective spaces. In any case, we prove here that they have the (multivariate) Hilbert polynomial of the diagonal. To achieve this, we first extend a Hilbert-polynomial formula for multiplicity-free varieties to (simple) normal-crossings schemes with multiplicity-free strata in products of projective spaces. Then we prove that a linked projective space is normal-crossings, by describing it locally in terms of Mustafin varieties. Finally, we use a relation between intersections of components of the linked projective space and certain polytopes in the tiling of a simplex associated to the linked net to prove that our formula for the Hilbert polynomial applies.

math.AG↗

arXiv2026

Asymptotic Behavior of Tropical Rank Functions

We show that the asymptotic behavior of the two main competing notions of rank of a linear series on a tropical curve is governed by asymptotic invariants, closely paralleling the theory of volumes in algebraic geometry. We introduce and study tropical notions of volume associated to both divisors and tropical modules. We prove optimal asymptotic results for each case. In addition, we show that the tropical volume is compatible with the tropicalization of curves.

math.AG↗

arXiv2026

Quiver matroids -- Matroid morphisms, quiver Grassmannians, their Euler characteristics and $\mathbb{F}_1$-points

In this paper, we introduce morphisms for matroids with coefficients (in the sense of Baker and Bowler) and quiver matroids. We investigate their basic properties, such as functoriality, duality, minors and cryptomorphic characterizations in terms of vectors, circuits and bases (a.k.a. Grassmann-Plücker functions). We generalize quiver matroids to quiver matroid bundles and construct their moduli space, which is an $\mathbb{F}_1$-analogue of a complex quiver Grassmannian. Eventually we introduce a suitable interpretation of $\mathbb{F}_1$-points for these moduli spaces, so that in 'nice' cases their number is equal to the Euler characteristic of the associated complex quiver Grassmannian.

math.CO↗

arXiv2026

Three lectures on tropical algebra

This document is a slightly expanded version of a series of talks given by J. Giansiracusa at the workshop `Geometry over semirings' at Universitat Autònoma de Barcelona in July 2025. In the first lecture we introduce tropical polynomials, ideals, congruences, and how the connection with tropical geometry is made via congruences of bend relations. Tropical geometry and matroid theory are telling us that we should focus attention on a narrow slice of the world of tropical algebra, and this leads to the theory of tropical ideals (as developed by Maclagan and Rincón) and an abundance of interesting open questions. In the second lecture we examine the relationship between Berkovich analytification and tropicalization from the perspective of bend relations, giving a refinement of Payne's influential limit theorem. In the third lecture we set aside geometry and focus on tropicalization via bend relations as a construction in commutative and non-commutative algebra. Constructions such as symmetric algebras, exterior algebras, matrix algebras, and Clifford algebras can be tropicalized. In the case of exterior algebras, the resulting tropical notion beautifully completes the picture of the Plücker embedding and gives a new perspective on the tropical Plücker relations. For matrix algebras and Clifford algebras, Morita theory becomes an interesting topic.

math.CO↗

arXiv2025

Neural Network for Subgrid Turbulence Modeling for Large Eddy Simulations

When simulating multiscale systems, where some fields cannot be fully prescribed despite their effects on the simulation's accuracy, closure models are needed. This phenomenon is observed in turbulent fluid dynamics, where Large Eddy Simulations (LES) depict global behavior while turbulence modeling introduces dissipation correspondent to smaller sub-grid scales. Recently, scientific machine learning techniques have emerged to address this problem by integrating traditional (physics-based) equations with data-driven (machine-learned) models, typically coupling numerical solvers with neural networks. This work presents a comprehensive workflow, encompassing high-fidelity data generation and post-processing, a priori learning, and a posteriori testing, where data-driven models enrich differential equations.

physics.flu-dyn↗

arXiv2025

Degenerations of maps to projective spaces

Degenerations of linear series on smooth projective varieties approaching multicomponent varieties $X$ give rise to certain quiver representations in the category of linear series over $X$, which yield rational maps from $X$ to the corresponding quiver Grassmannians of codimension 1 subspaces. We describe these quiver Grassmannians for the case of the simplest quiver, arising when $X$ has only two components. We prove that they are reduced, local complete intersections whose components are rational of the same dimension. Also, we show that they are limits of projective spaces when they do arise from degenerations, and thus are special fibers of certain Mustafin varieties. Finally, we address a Riemann--Roch question for these quiver representations.

math.AG↗

arXiv2024

Quiver representations arising from degenerations of linear series, II

We describe all the schematic limits of families of divisors associated to a given family of rank-$r$ linear series on a one-dimensional family of projective varieties degenerating to a connected reduced projective scheme $X$ defined over any field, under the assumption that the total space of the family is regular along $X$. More precisely, the degenerating family gives rise to a special quiver $Q$, called a \emph{$\mathbb{Z}^n$-quiver}, a special representation $\mathfrak L$ of $Q$ in the category of line bundles over $X$, called a \emph{maximal exact linked net}, and a special subrepresentation $\mathfrak V$ of the representation $H^0(X,\mathfrak L)$ induced from $\mathfrak L$ by taking global sections, called a \emph{pure exact finitely generated linked net} of dimension $r+1$. Given $\mathfrak g=(Q,\mathfrak L,\mathfrak V)$ satisfying these properties, we prove that the quiver Grassmanian $\mathbb{LP}(\mathfrak{V})$ of subrepresentations of $\mathfrak{V}$ of pure dimension 1, called a \emph{linked projective space}, is local complete intersection, reduced and of pure dimension $r$. Furthermore, we prove that there is a morphism $\mathbb{LP}(\mathfrak{V})\to\text{Hilb}_X$, and that its image parameterizes all the schematic limits of divisors along the degenerating family of linear series if $\mathfrak g$ arises from one.

math.AG↗

arXiv2022

Quiver representations arising from degenerations of linear series, I

We give a local characterization for when certain quiver representations in semisimple Abelian categories are semisimple, among them those arising from degenerations of linear series. This paper is the first of two, aimed to describe all the schematic limits of families of divisors associated to a given family of linear series on a one-dimensional family of projective varieties degenerating to a connected reduced projective scheme $X$ defined over any field, under the assumption that the total space of the family is regular along $X$, by means of certain quiver Grassmannians.

math.AG↗