Counting rational points on hypersurfaces and higher order expansions

TL;DR

This paper develops a general approach to obtain multi-term asymptotics for the number of integer representations by forms and applies it to count rational points on hypersurfaces, extending classical results with higher order expansions.

Contribution

It introduces a new, more general method to derive multi-term asymptotics for counting solutions to polynomial equations, including rational points on hypersurfaces.

Findings

Derived multi-term asymptotics for representations of integers by forms.

Provided higher order expansions for rational points on hypersurfaces.

Interpreted lower order terms in the asymptotic formulas.

Abstract

We study the number of representations of an integer n=F(x_1,...,x_s) by a homogeneous form in sufficiently many variables. This is a classical problem in number theory to which the circle method has been succesfully applied to give an asymptotic for the number of such representations where the integer vector (x_1,...,x_s) is restricted to a box of side length P for P sufficiently large. In the special case of Waring's problem, Vaughan and Wooley have recently established for the first time a higher order expansion for the corresponding asymptotic formula. Via a different and much more general approach we derive a multi-term asymptotic for this problem for general forms F(x_1,...,x_s) and give an interpretation for the occurring lower order terms. As an application we derive higher order expansions for the number of rational points of bounded anticanonical height on the projective hypersurface F(x_1,...,x_s)=0 for forms F in sufficiently many variables.