Higher Moments of Arithmetic Functions in Short Intervals: A Geometric Perspective

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 ℓ-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.

NOETHER–LEFSCHETZ THEORY AND NÉRON–SEVERI GROUP

Let Z be a closed subscheme of a smooth complex projective complete intersection variety Y ⊆ ℙN, with dim Y = 2r + 1 ≥ 3. We describe the Néron–Severi group NSr(X) of a general smooth hypersurface X ⊂ Y of sufficiently large degree containing Z.

On the topology of full non-degenerate complete intersection variety

Let h1(u),…, hk(u) be Laurent polynomials of m-variables and letbe a non-degenerate complete intersection variety. Such an intersection variety appears as an exceptional divisor of a resolution of non-degenerate complete intersection varieties with an isolated singularity at the origin (Ok4]).