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arXiv 0907.0842math.AGmath.NT
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拟Galois闭算术概型的自同构群

Automorphism Groups of Quasi-galois Closed Arithmetic Schemes

Feng-Wen An

摘要:

假设$X$和$Y$是算术方案,即,$Spec(\mathbb{Z})$上有限型积分格式则称$X$在$Y$上是拟伽罗瓦闭的,如果$X$在某个代数闭域上有唯一的共轭,其中$X$在$Y$上的共轭是以明显的方式定义的.现在假设$ϕ:X\to Y$是有限型满射,使得$X$在$Y$上是拟伽罗瓦闭的.本文的主要定理是:函数域$ k(X)$是$k(Y)$的正则伽罗瓦扩张,自同构群${Aut}(X/Y)$同构于伽罗瓦群$Gal(k(X)/k(Y))$,特别地,$ϕ$必须是仿射的.此外,令$\dim X=\dim Y$ .则$X$是$Y$在Suslin-Voevodsky意义下的伪伽罗瓦覆盖.

英文摘要:

Assume that $X$ and $Y$ are arithmetic schemes, i.e., integral schemes of finite types over $Spec(\mathbb{Z})$. Then $X$ is said to be quasi-galois closed over $Y$ if $X$ has a unique conjugate over $Y$ in some certain algebraically closed field, where the conjugate of $X$ over $Y$ is defined in an evident manner. Now suppose that $ϕ:X\to Y$ is a surjective morphism of finite type such that $X$ is quasi-galois closed over $Y$. In this paper the main theorem says that the function field $ k(X)$ is canonically a Galois extension of $k(Y)$ and the automorphism group ${Aut}(X/Y)$ is isomorphic to the Galois group $Gal(k(X)/k(Y))$; in particular, $ϕ$ must be affine. Moreover, let $\dim X=\dim Y$. Then $X$ is a pseudo-galois cover of $Y$ in the sense of Suslin-Voevodsky.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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