activity
20132026
most citedThe universal tropical Jacobian and the skeleton of the Esteves' universal Jacobian

20 citations · 35 across the 14 of their papers we have counts for

collaborators

19 papers

math.AG2026

Extending Andreotti's proof of Torelli's theorem to nodal curves

Alex Abreu, Marco Pacini, Nicola Pagani

Let be a connected nodal curve of genus over an algebraically closed field of characteristic zero. Let \[ A(C)=\Big(J(C), {\overline{P^{g-1}_C}}, Θ(C) \Big) \] be the s…

math.CO2023

A Torelli theorem for graphs via quasistable divisors

Alex Abreu, Marco Pacini

The Torelli theorem establishes that the Jacobian of a smooth projective curve, together with the polarization provided by the theta divisor, fully characterizes the curve. In the…

math.AG2023

Splitting the cohomology of Hessenberg varieties and e-positivity of chromatic symmetric functions

Alex Abreu, Antonio Nigro

For each indifference graph, there is an associated regular semisimple Hessenberg variety, whose cohomology recovers the chromatic symmetric function of the graph. The decompositio…

math.AG2023

Wall-crossing of universal Brill-Noether classes

Alex Abreu, Nicola Pagani

We give an explicit graph formula, in terms of decorated boundary strata classes, for the wall-crossing of universal Brill-Noether classes. More precisely, fix n>0 and d<g , and tw…

math.AG2022

Parabolic Lusztig varieties and chromatic symmetric functions

Alex Abreu, Antonio Nigro

The characters of Kazhdan--Lusztig elements of the Hecke algebra over (and in particular, the chromatic symmetric function of indifference graphs) are completely encoded in t…

math.AG2022★ 1 cited

A geometric approach to characters of Hecke algebras

Alex Abreu, Antonio Nigro

To any element of a connected, simply connected, semisimple complex algebraic group G and a choice of an element of the corresponding Weyl group there is an associated Lusztig vari…

math.AG2022★ 1 cited

An update on Haiman's conjectures

Alex Abreu, Antonio Nigro

We revisit Haiman's conjecture on the relations between characters of Kazdhan-Lusztig basis elements of the Hecke algebra over the symmetric group. The conjecture asserts that, for…

math.AG2022

On moduli spaces of roots in algebraic and tropical geometry

Alex Abreu, Marco Pacini, Matheus Secco

In this paper we construct a tropical moduli space parametrizing roots of divisors on tropical curves. We study the relation between this space and the skeleton of Jarvis moduli sp…

math.AG2022

Degree-2 Abel maps and hyperelleptic curves

Alex Abreu, Sally Andria, Marco Pacini

In this paper we resolve the degree-2 Abel map for nodal curves. Our results are based on a previous work of the authors reducing the problem of the resolution of the Abel map to a…

math.AG2020

The moduli space of quasistable spin curves

Alex Abreu, Marco Pacini, Danny Taboada

We study a compactification of the moduli space of theta characteristics, giving a modular interpretation of the geometric points and describing the boundary stratification. This s…

math.AG2020

Abel Maps for nodal curves via tropical geometry

Alex Abreu, Sally Andria, Marco Pacini

We consider Abel maps for regular smoothing of nodal curves with values in the Esteves compactified Jacobian. In general, these maps are just rational, and an interesting question…

math.CO2020

Chromatic symmetric functions from the modular law

Alex Abreu, Antonio Nigro

In this article we show how to compute the chromatic quasisymmetric function of indifference graphs from the modular law introduced by Guay-Paquet. We provide an algorithm which wo…

math.CO2020★ 8 cited

A symmetric function of increasing forests

Alex Abreu, Antonio Nigro

For an indifference graph we define a symmetric function of increasing spanning forests of . We prove that this symmetric function satisfies certain linear relations, which…

math.AG2019★ 3 cited

A universal tropical Jacobian over $M_g^{\trop}$

Alex Abreu, Sally Andria, Marco Pacini +1

We introduce and study polystable divisors on a tropical curve, which are the tropical analogue of polystable torsion-free rank-1 sheaves on a nodal curve. We construct a universal…

math.AG2019★ 1 cited

The resolution of the universal Abel map via tropical geometry and applications

Alex Abreu, Marco Pacini

Let and be nonnegative integers and a sequence of integers summing up to . Let be the moduli space of…

math.AG2018★ 20 cited

The universal tropical Jacobian and the skeleton of the Esteves' universal Jacobian

Alex Abreu, Marco Pacini

For each universal genus- polarization of degree , we construct a universal tropical Jacobian as a generalized cone complex over the moduli space of stab…

math.AG2016★ 1 cited

The automorphism group of and

Alex Abreu, Marco Pacini

In this paper we show that the automorphism groups of and are isomorphic to the permutation group for , whi…

math.AG2014

Enriched curves and their tropical counterpart

Alex Abreu, Marco Pacini

In her Ph.D. thesis, Mainò introduced the notion of enriched structure on stable curves and constructed their moduli space. In this paper we give a tropical notion of enriched stru…

math.AG2013

On the geometry of Abel maps for nodal curves

Alex Abreu, Juliana Coelho, Marco Pacini

In this paper we give local conditions to the existence of Abel maps for nodal curves that are limits of Abel maps for smooth curves. We use this result to construct Abel maps for…