Higher moments of arithmetic functions in short intervals: a geometric perspective. (English) Zbl 1472.11255
Summary: We study the geometry associated to the distribution of certain arithmetic functions, including the von Mangoldt function and the Möbius function, in short intervals of polynomials over a finite field \(\mathbb{F}_q\). Using the Grothendieck-Lefschetz trace formula, we reinterpret each moment of these distributions as a point-counting problem on a highly singular complete intersection variety. We compute part of the \(\ell\)-adic cohomology of these varieties, corresponding to an asymptotic bound on each moment for fixed degree \(n\) in the limit as \(q \to \infty \). The results of this paper can be viewed as a geometric explanation for asymptotic results that can be proved using analytic number theory over function fields.
MSC:
11N37 | Asymptotic results on arithmetic functions |
11R58 | Arithmetic theory of algebraic function fields |
14F20 | Étale and other Grothendieck topologies and (co)homologies |
11T55 | Arithmetic theory of polynomial rings over finite fields |