The absolute Galois group of subfields of the field of totally $\boldsymbol{S}$-adic numbers

Abstract

For a finite set $S$ of local primes of a countable Hilbertian field $K$ and for $\sigma_1,\ldots,\sigma_e\in\Gal(K)$ we denote the field of totally $S$-adic numbers by $\K_{tot,S}$, the fixed field of $\sigma_1,\ldots,\sigma_e$ in $\K_{tot,S}$ by $\K_{tot,S}({\mathbf \sigma})$, and the maximal Galois extension of $K$ in $\KtotS({\mathbf \sigma})$ by $\KtotS[{\mathbf \sigma}]$. We prove that for almost all ${\mathbf \sigma}\in\Gal(K)^e$ the absolute Galois group of $\K_{tot,S}[{\mathbf \sigma}]$ is isomorphic to the free product of $\hat{F}_\omega$ and a free product of local factors over $S$.