Algebraic relations over finite fields that preserve the endomorphism rings of CM $j$-invariants

Fuente: arXiv
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Main Authors: Campagna, Francesco, Dill, Gabriel Andreas
Format: Preprint
Published: 2023
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author Campagna, Francesco
Dill, Gabriel Andreas
author_facet Campagna, Francesco
Dill, Gabriel Andreas
contents We characterise the integral affine plane curves over a finite field $k$ with the property that all but finitely many of their $\overline{k}$-points have coordinates that are $j$-invariants of elliptic curves with isomorphic endomorphism rings. This settles a finite field variant of the André-Oort conjecture for $Y(1)^2_\mathbb{C}$, which is a theorem of André. We use our result to solve the modular support problem for function fields of positive characteristic.
format Preprint
id arxiv_https___arxiv_org_abs_2308_10976
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Algebraic relations over finite fields that preserve the endomorphism rings of CM $j$-invariants
Campagna, Francesco
Dill, Gabriel Andreas
Number Theory
Algebraic Geometry
11G15, 11G18
We characterise the integral affine plane curves over a finite field $k$ with the property that all but finitely many of their $\overline{k}$-points have coordinates that are $j$-invariants of elliptic curves with isomorphic endomorphism rings. This settles a finite field variant of the André-Oort conjecture for $Y(1)^2_\mathbb{C}$, which is a theorem of André. We use our result to solve the modular support problem for function fields of positive characteristic.
title Algebraic relations over finite fields that preserve the endomorphism rings of CM $j$-invariants
topic Number Theory
Algebraic Geometry
11G15, 11G18
url https://arxiv.org/abs/2308.10976