Density of solutions for systems of forms

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Lampert, Amichai
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918132407336960
author Lampert, Amichai
author_facet Lampert, Amichai
contents Let $K$ be a field of characteristic zero over which every diagonal form in sufficiently many variables admits a nontrivial solution. For example, $K$ may be a totally imaginary number field or a finite extension of a $p$-adic field. Suppose $f_1,\ldots,f_s$ are forms of degree $d$ over $K.$ Bik, Draisma and Snowden recently proved that there exists a constant $B = B(d,s,K)$ such that the rational solutions to the system of equations $f_1=\ldots=f_s = 0$ are Zariski dense, as long as the Birch rank of $f_1,\ldots,f_s$ is greater than $B.$ We establish an effective bound for this constant, improving vastly on the astronomical bound coming from their proof. Our result has applications for surjectivity of polynomial maps and for the Hardy-Littlewood circle method.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11514
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Density of solutions for systems of forms
Lampert, Amichai
Number Theory
Algebraic Geometry
11D72, 11G25, 11G35, 11P55, 14G05
Let $K$ be a field of characteristic zero over which every diagonal form in sufficiently many variables admits a nontrivial solution. For example, $K$ may be a totally imaginary number field or a finite extension of a $p$-adic field. Suppose $f_1,\ldots,f_s$ are forms of degree $d$ over $K.$ Bik, Draisma and Snowden recently proved that there exists a constant $B = B(d,s,K)$ such that the rational solutions to the system of equations $f_1=\ldots=f_s = 0$ are Zariski dense, as long as the Birch rank of $f_1,\ldots,f_s$ is greater than $B.$ We establish an effective bound for this constant, improving vastly on the astronomical bound coming from their proof. Our result has applications for surjectivity of polynomial maps and for the Hardy-Littlewood circle method.
title Density of solutions for systems of forms
topic Number Theory
Algebraic Geometry
11D72, 11G25, 11G35, 11P55, 14G05
url https://arxiv.org/abs/2507.11514