A Torelli theorem for graphs via quasistable divisors

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 case of nodal curves, there exists a concept known as fine compactified Jacobian. The fine compactified Jacobian of a cu...

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Main Authors: Alex Abreu, Marco Pacini
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Forum of Mathematics, Sigma
Online Access:https://www.cambridge.org/core/product/identifier/S205050942400135X/type/journal_article
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author Alex Abreu
Marco Pacini
author_facet Alex Abreu
Marco Pacini
author_sort Alex Abreu
collection DOAJ
description 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 case of nodal curves, there exists a concept known as fine compactified Jacobian. The fine compactified Jacobian of a curve comes with a natural stratification that can be regarded as a poset. Furthermore, this poset is entirely determined by the dual graph of the curve and is referred to as the poset of quasistable divisors on the graph. We present a combinatorial version of the Torelli theorem, which demonstrates that the poset of quasistable divisors of a graph completely determines the biconnected components of the graph (up to contracting separating edges). Moreover, we achieve a natural extension of this theorem to tropical curves.
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series Forum of Mathematics, Sigma
spelling doaj-art-055690b473f64188a11c7ffb08cc37c12025-02-03T10:39:38ZengCambridge University PressForum of Mathematics, Sigma2050-50942025-01-011310.1017/fms.2024.135A Torelli theorem for graphs via quasistable divisorsAlex Abreu0Marco Pacini1Universidade Federal Fluminense, Instituto de Matemática e Estatística, Rua Prof. M. W. de Freitas, S/N, 24210-201 Niterói, Brazil;Universidade Federal Fluminense, Instituto de Matemática e Estatística, Rua Prof. M. W. de Freitas, S/N, 24210-201 Niterói, Brazil; E-mail: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 case of nodal curves, there exists a concept known as fine compactified Jacobian. The fine compactified Jacobian of a curve comes with a natural stratification that can be regarded as a poset. Furthermore, this poset is entirely determined by the dual graph of the curve and is referred to as the poset of quasistable divisors on the graph. We present a combinatorial version of the Torelli theorem, which demonstrates that the poset of quasistable divisors of a graph completely determines the biconnected components of the graph (up to contracting separating edges). Moreover, we achieve a natural extension of this theorem to tropical curves.https://www.cambridge.org/core/product/identifier/S205050942400135X/type/journal_article
spellingShingle Alex Abreu
Marco Pacini
A Torelli theorem for graphs via quasistable divisors
Forum of Mathematics, Sigma
title A Torelli theorem for graphs via quasistable divisors
title_full A Torelli theorem for graphs via quasistable divisors
title_fullStr A Torelli theorem for graphs via quasistable divisors
title_full_unstemmed A Torelli theorem for graphs via quasistable divisors
title_short A Torelli theorem for graphs via quasistable divisors
title_sort torelli theorem for graphs via quasistable divisors
url https://www.cambridge.org/core/product/identifier/S205050942400135X/type/journal_article
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