Stratifying moduli spaces of Higgs bundles and the Hitchin morphism

Fuente: arXiv
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Main Authors: Patel, Aryaman, Weissmann, Dario
Format: Preprint
Published: 2026
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author Patel, Aryaman
Weissmann, Dario
author_facet Patel, Aryaman
Weissmann, Dario
contents We study the behavior of slope-stability of reflexive twisted sheaves over a normal projective variety $X$ under pullback along a cover. Slope-stability is always preserved if the cover does not factor via a quasi-étale cover. Fixing the rank, there is one quasi-étale cover that checks whether a twisted sheaf remains slope-stable on all Galois covers, yielding a stratification of the moduli space of slope-stable Higgs-bundles. As an application, we determine the image of the Hitchin morphism restricted to the smallest closed stratum of the Dolbeault moduli space when $X$ is smooth. This allows us to determine the image of the Hitchin morphism from the Dolbeault moduli space when $X$ is a hyperelliptic or abelian variety in characteristic $p\ge0$. In particular, we show that Chen-Ngô's conjecture holds for hyperelliptic varieties in characteristic $0$.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08597
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Stratifying moduli spaces of Higgs bundles and the Hitchin morphism
Patel, Aryaman
Weissmann, Dario
Algebraic Geometry
We study the behavior of slope-stability of reflexive twisted sheaves over a normal projective variety $X$ under pullback along a cover. Slope-stability is always preserved if the cover does not factor via a quasi-étale cover. Fixing the rank, there is one quasi-étale cover that checks whether a twisted sheaf remains slope-stable on all Galois covers, yielding a stratification of the moduli space of slope-stable Higgs-bundles. As an application, we determine the image of the Hitchin morphism restricted to the smallest closed stratum of the Dolbeault moduli space when $X$ is smooth. This allows us to determine the image of the Hitchin morphism from the Dolbeault moduli space when $X$ is a hyperelliptic or abelian variety in characteristic $p\ge0$. In particular, we show that Chen-Ngô's conjecture holds for hyperelliptic varieties in characteristic $0$.
title Stratifying moduli spaces of Higgs bundles and the Hitchin morphism
topic Algebraic Geometry
url https://arxiv.org/abs/2601.08597