Tate kernels, etale K-theory and the Gross kernel

TL;DR

This paper investigates generalized Tate kernels in relation to étale K-theory and the Gross kernel, establishing isomorphisms under certain conjectures and applying results to capitulation kernels.

Contribution

It introduces a new class of Tate kernels with properties linking them to étale K-theory and the Gross kernel, assuming the Gross-Jaulent conjecture.

Findings

Isomorphism between Tate kernels and étale K-theory modulo p^n under specific conditions.

Periodic behavior of Tate kernels modulo powers of p.

Lower bounds for capitulation kernels in étale K-theory.

Abstract

For an odd prime $p$ and a number field $F$ containing a $p$th root of unity, we study generalised Tate kernels, $D_F^{[i,n]}$, for $i\in \mathbb{Z}$ and $n\geq 1$, having the properties that if $i\geq 2$ and if either $p$ does not divide $i$ or $\mu_{p^n}\subset F$ then there are natural isomorphisms $D_F^{[i,n]}\cong K^{\mbox{\tiny \'et}}_{2i-1}(O_F^S)/p^n$, and that they are periodic modulo a power of $p$ which depends on $F$ and $n$. Our main result is that if the Gross-Jaulent conjecture holds for $(F,p)$ then there is a natural isomorphism $D_F^{[i,n]}\cong\mathcal{E}_F/p^n$ where $\mathcal{E}_F$ is the Gross kernel. We apply this result to compute lower bounds for capitulation kernels in even \'etale $K$-theory.