Reconstruction of hypersurfaces from their invariants

Fuente: arXiv
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Main Author: Bouchet, Thomas
Format: Preprint
Published: 2024
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author Bouchet, Thomas
author_facet Bouchet, Thomas
contents Let $K$ be a field of characteristic $0$. We present an explicit algorithm that, given the invariants of a generic homogeneous polynomial $f$ under the linear action of $\mathrm{GL}_n$ or $\mathrm{SL}_n$, returns a polynomial differing from $f$ only by a linear change of variables with coefficients in a finite extension of $K$. Our approach uses the theory of covariants and the Veronese embeddings to characterize the linear equivalence class of a homogeneous polynomial through equations whose coefficients are invariants. As applications, we derive explicit formulas for reconstructing of a generic non-hyperelliptic curve of genus 4 from its invariants, as well as reconstructing generic non-hyperelliptic curves of genus 3 from their Dixmier-Ohno invariants. In both cases, the coefficients of the reconstructed curve lie in its field of moduli.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17490
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Reconstruction of hypersurfaces from their invariants
Bouchet, Thomas
Commutative Algebra
Algebraic Geometry
Let $K$ be a field of characteristic $0$. We present an explicit algorithm that, given the invariants of a generic homogeneous polynomial $f$ under the linear action of $\mathrm{GL}_n$ or $\mathrm{SL}_n$, returns a polynomial differing from $f$ only by a linear change of variables with coefficients in a finite extension of $K$. Our approach uses the theory of covariants and the Veronese embeddings to characterize the linear equivalence class of a homogeneous polynomial through equations whose coefficients are invariants. As applications, we derive explicit formulas for reconstructing of a generic non-hyperelliptic curve of genus 4 from its invariants, as well as reconstructing generic non-hyperelliptic curves of genus 3 from their Dixmier-Ohno invariants. In both cases, the coefficients of the reconstructed curve lie in its field of moduli.
title Reconstruction of hypersurfaces from their invariants
topic Commutative Algebra
Algebraic Geometry
url https://arxiv.org/abs/2403.17490