A genus formula for the positive étale wild kernel

Abstract

Let $F$ be a number field and let $i\ge 2$ be an integer. In this paper, we study the positive étale wild kernel $\mathrm{WK}^{\mbox{ét},+}_{2i-2}F$, which is the twisted analogue of the $2$-primary part of the narrow class group. If $E/F$ is a Galois extension of number fields with Galois group $G$, we prove a genus formula relating the order of the groups $ (\mathrm{WK}^{\mbox{ét},+}_{2i-2}E)_{G}$ and $\mathrm{WK}^{\mbox{ét},+}_{2i-2}F$.

16 pages