English

A Tauberian Theorem for $\ell$-adic Sheaves on $\mathbb A^1$

Algebraic Geometry 2015-05-19 v1 Number Theory

Abstract

Let KL1(R)K\in L^1(\mathbb R) and let fL(R)f\in L^\infty(\mathbb R) be two functions on R\mathbb R. The convolution (Kf)(x)=RK(xy)f(y)dy(K\ast f)(x)=\int_{\mathbb R}K(x-y)f(y)dy can be considered as an average of ff with weight defined by KK. Wiener's Tauberian theorem says that under suitable conditions, if limx(Kf)(x)=limx(KA)(x)\lim_{x\to \infty}(K\ast f)(x)=\lim_{x\to \infty} (K\ast A)(x) for some constant AA, then limxf(x)=A.\lim_{x\to \infty}f(x)=A. We prove the following \ell-adic analogue of this theorem: Suppose K,F,GK,F, G are perverse \ell-adic sheaves on the affine line A\mathbb A over an algebraically closed field of characteristic pp (pp\not=\ell). Under suitable conditions, if (KF)η(KG)η,(K\ast F)|_{\eta_\infty}\cong (K\ast G)|_{\eta_\infty}, then FηGη,F|_{\eta_\infty}\cong G|_{\eta_\infty}, where η\eta_\infty is the spectrum of the local field of A\mathbb A at \infty.

Keywords

Cite

@article{arxiv.1006.0789,
  title  = {A Tauberian Theorem for $\ell$-adic Sheaves on $\mathbb A^1$},
  author = {Lei Fu},
  journal= {arXiv preprint arXiv:1006.0789},
  year   = {2015}
}

Comments

To appear in Science in China, an issue dedicated to Wang Yuan on the occation of his 80th birthday

R2 v1 2026-06-21T15:31:52.597Z