Effective equidistribution of Galois orbits for mildly regular test functions
Emanuel Carneiro, Mithun Kumar Das
TL;DR
This work studies effective versions of Bilu's equidistribution for Galois orbits of small-height points in the $N$-dimensional torus, connecting convergence to the regularity of mildly regular test functions. It develops a Fourier-analytic framework that extends prior work and yields quantitative bounds on the discrepancy $oldsymbol{\\mathcal{E}}(F,oldsymbol{\xi})$ in terms of the Weil height $h(oldsymbol{\xi})$ and the generalized height $h_{oldsymbol{D}}(oldsymbol{\xi})$, under two complementary regularity regimes: (i) regularity on the Fourier side via a class $oldsymbol{\mathcal{A}}$ and (ii) angular regularity at the log-radius via a modulus of continuity or Hölder control. The main results (Theorems 1 and 5, with Corollaries 3 and 6) establish sharp qualitative dependencies, including Hölder exponents up to $\gamma\le 1/2$, and show how angular regularity can yield comparable gains to full Lipschitz regularity in the multi-dimensional setting. The paper also provides sharpness results, and appendices connect the framework to multidimensional angular discrepancy and complete a density-based proof of Bilu's theorem for mildly regular test functions, highlighting the practical impact on discrepancy bounds and equidistribution in higher dimensions.
Abstract
In this paper we provide a detailed study on effective versions of the celebrated Bilu's equidistribution theorem for Galois orbits of sequences of points of small height in the $N$-dimensional algebraic torus, identifying the qualitative dependence of the convergence in terms of the regularity of the test functions considered. We develop a general Fourier analysis framework that extends previous results obtained by Petsche (2005), and by D'Andrea, Narváez-Clauss and Sombra (2017).
