The Other Group of as Galois Extension

Lex E. Renner

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arXiv · 0804.4153

The Other Group of as Galois Extension

Lex E. Renner

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Abstract

Let $k\subseteq K$ be a finite Galois extension of fields with Galois group $G$. Let $\mathscr{G}$ be the automorphism $k$-group scheme of $K$. We construct a canonical $k$-subgroup scheme $\underline{G}\subset\mathscr{G}$ with the property that $Spec_k(K)$ is a $k$-torsor for $\underline{G}$. $\underline{G}$ is a constant $k$-group if and only if $G$ is abelian, in which case $G=\underline{G}$.

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Lex E. Renner. 2008-04-25. The Other Group of as Galois Extension. https://arxiv.org/abs/0804.4153

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