Differentiably simple rings and ring extensions defined by $p$-basis

Fuente: arXiv
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Hauptverfasser: de Andrés, Celia del Buey, Sulca, Diego, Villamayor, Orlando E.
Format: Preprint
Veröffentlicht: 2022
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author de Andrés, Celia del Buey
Sulca, Diego
Villamayor, Orlando E.
author_facet de Andrés, Celia del Buey
Sulca, Diego
Villamayor, Orlando E.
contents We review the concept of differentiably simple ring and we give a new proof of Harper's Theorem on the characterization of Noetherian differentiably simple rings in positive characteristic. We then study flat families of differentiably simple rings, or equivalently, finite flat extensions of rings which locally admit $p$-basis. These extensions are called "Galois extensions of exponent one". For such an extension $A\subset C$, we introduce an $A$-scheme, called the "Yuan scheme", which parametrizes subextensions $A\subset B\subset C$ such that $B\subset C$ is Galois of a fixed rank. So, roughly, the Yuan scheme can be thought of as a kind of Grassmannian of Galois subextensions. We finally prove that the Yuan scheme is smooth and compute the dimension of the fibers.
format Preprint
id arxiv_https___arxiv_org_abs_2211_09125
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Differentiably simple rings and ring extensions defined by $p$-basis
de Andrés, Celia del Buey
Sulca, Diego
Villamayor, Orlando E.
Commutative Algebra
Algebraic Geometry
13B05, 14M15, 14L17
We review the concept of differentiably simple ring and we give a new proof of Harper's Theorem on the characterization of Noetherian differentiably simple rings in positive characteristic. We then study flat families of differentiably simple rings, or equivalently, finite flat extensions of rings which locally admit $p$-basis. These extensions are called "Galois extensions of exponent one". For such an extension $A\subset C$, we introduce an $A$-scheme, called the "Yuan scheme", which parametrizes subextensions $A\subset B\subset C$ such that $B\subset C$ is Galois of a fixed rank. So, roughly, the Yuan scheme can be thought of as a kind of Grassmannian of Galois subextensions. We finally prove that the Yuan scheme is smooth and compute the dimension of the fibers.
title Differentiably simple rings and ring extensions defined by $p$-basis
topic Commutative Algebra
Algebraic Geometry
13B05, 14M15, 14L17
url https://arxiv.org/abs/2211.09125